diff --git a/n3fit/src/n3fit/scripts/evolven3fit_new.py b/n3fit/src/n3fit/scripts/evolven3fit_new.py
index 5bc6e14cb8..004f6fa52c 100644
--- a/n3fit/src/n3fit/scripts/evolven3fit_new.py
+++ b/n3fit/src/n3fit/scripts/evolven3fit_new.py
@@ -103,6 +103,11 @@ def main():
         default=None,
         help="ev_op_iterations for the EXA theory",
     )
+    parser.add_argument(
+        "--use-fhmruvv",
+        action="store_true",
+        help="Use the FHMRUVV N3LO splitting splitting functions",
+    )
     subparsers = parser.add_subparsers(title="actions", dest="actions")
     construct_eko_parser(subparsers)
     construct_eko_photon_parser(subparsers)
@@ -112,7 +117,11 @@ def main():
     op_card_info = {
         "configs": {"n_integration_cores": args.n_cores, "ev_op_iterations": args.ev_op_iterations}
     }
+
     theory_card_info = {}
+    if args.use_fhmruvv:
+        theory_card_info["use_fhmruvv"] = args.use_fhmruvv
+
     if args.actions == "evolve":
         cli.cli_evolven3fit_new(
             args.configuration_folder,
diff --git a/validphys2/src/validphys/datafiles/theory.db b/validphys2/src/validphys/datafiles/theory.db
index 1d2e71a9c0..9e8c595136 100644
Binary files a/validphys2/src/validphys/datafiles/theory.db and b/validphys2/src/validphys/datafiles/theory.db differ
diff --git a/validphys2/src/validphys/scalevariations/pointprescriptions.yaml b/validphys2/src/validphys/scalevariations/pointprescriptions.yaml
index 859eea5d38..d76d2ca400 100644
--- a/validphys2/src/validphys/scalevariations/pointprescriptions.yaml
+++ b/validphys2/src/validphys/scalevariations/pointprescriptions.yaml
@@ -21,7 +21,7 @@
 'n3lo 3pt hadronic': ['(0, 0, 0, 0)','(1, 0, 0, 0)','(2, 0, 0, 0)','(3, 0, 0, 0)','(4, 0, 0, 0)','(5, 0, 0, 0)','(6, 0, 0, 0)','(7, 0, 0, 0)','(8, 0, 0, 0)','(9, 0, 0, 0)','(10, 0, 0, 0)','(11, 0, 0, 0)','(12, 0, 0, 0)','(13, 0, 0, 0)','(14, 0, 0, 0)','(15, 0, 0, 0)','(16, 0, 0, 0)','(17, 0, 0, 0)','(18, 0, 0, 0)','(19, 0, 0, 0)','(0, 1, 0, 0)','(0, 2, 0, 0)','(0, 3, 0, 0)','(0, 4, 0, 0)','(0, 5, 0, 0)','(0, 6, 0, 0)','(0, 7, 0, 0)','(0, 8, 0, 0)','(0, 9, 0, 0)','(0, 10, 0, 0)','(0, 11, 0, 0)','(0, 12, 0, 0)','(0, 13, 0, 0)','(0, 14, 0, 0)','(0, 15, 0, 0)','(0, 16, 0, 0)','(0, 17, 0, 0)','(0, 18, 0, 0)','(0, 19, 0, 0)','(0, 20, 0, 0)','(0, 21, 0, 0)','(0, 0, 1, 0)','(0, 0, 2, 0)','(0, 0, 3, 0)','(0, 0, 4, 0)','(0, 0, 5, 0)','(0, 0, 6, 0)','(0, 0, 7, 0)','(0, 0, 8, 0)','(0, 0, 9, 0)','(0, 0, 10, 0)','(0, 0, 11, 0)','(0, 0, 12, 0)','(0, 0, 13, 0)','(0, 0, 14, 0)','(0, 0, 15, 0)','(0, 0, 0, 1)','(0, 0, 0, 2)','(0, 0, 0, 3)','(0, 0, 0, 4)','(0, 0, 0, 5)','(0, 0, 0, 6)', '(1, 0.5 hadronic)', '(1, 2 hadronic)','(-1, -1)','(1, 1)']
 # N3LO 7 point scale variations
 'n3lo 7 point': ['(0, 0, 0, 0)', '(2, 1)', '(0.5, 1)', '(1, 2)', '(1, 0.5)', '(2, 2)', '(0.5, 0.5)']
-# N3LO 3 point hadronic renormalization scale variations
-'n3lo 3r point hadronic': ['(0, 0, 0, 0)', '(1, 0.5 hadronic)', '(1, 2 hadronic)']
-# N3LO 3 point missing renormalization scale variations
-'n3lo 3r point missing': ['(0, 0, 0, 0)', '(1, 0.5 missing)', '(1, 2 missing)']
+# N3LO full IHOU + 7 point scale variations with FHMV splittings
+'n3lo fhmv full thcovmat': ['(0, 0, 0, 0, 0, 0, 0)','(1, 0, 0, 0, 0, 0, 0)','(2, 0, 0, 0, 0, 0, 0)','(0, 1, 0, 0, 0, 0, 0)','(0, 2, 0, 0, 0, 0, 0)', '(0, 0, 1, 0, 0, 0, 0)','(0, 0, 2, 0, 0, 0, 0)','(0, 0, 0, 1, 0, 0, 0)','(0, 0, 0, 2, 0, 0, 0)','(0, 0, 0, 0, 1, 0, 0)','(0, 0, 0, 0, 2, 0, 0)','(0, 0, 0, 0, 0, 1, 0)','(0, 0, 0, 0, 0, 2, 0)','(0, 0, 0, 0, 0, 0, 1)','(0, 0, 0, 0, 0, 0, 2)','(2, 1)', '(0.5, 1)', '(1, 2)', '(1, 0.5)', '(2, 2)', '(0.5, 0.5)','(-1, -1)','(1, 1)']
+# N3LO full IHOU + 3 point scale variations for hadronic dasasets with FHMV splittings
+'n3lo fhmv 3pt hadronic': ['(0, 0, 0, 0, 0, 0, 0)','(1, 0, 0, 0, 0, 0, 0)','(2, 0, 0, 0, 0, 0, 0)','(0, 1, 0, 0, 0, 0, 0)','(0, 2, 0, 0, 0, 0, 0)', '(0, 0, 1, 0, 0, 0, 0)','(0, 0, 2, 0, 0, 0, 0)','(0, 0, 0, 1, 0, 0, 0)','(0, 0, 0, 2, 0, 0, 0)','(0, 0, 0, 0, 1, 0, 0)','(0, 0, 0, 0, 2, 0, 0)','(0, 0, 0, 0, 0, 1, 0)','(0, 0, 0, 0, 0, 2, 0)','(0, 0, 0, 0, 0, 0, 1)','(0, 0, 0, 0, 0, 0, 2)','(1, 0.5 hadronic)', '(1, 2 hadronic)','(-1, -1)','(1, 1)']
diff --git a/validphys2/src/validphys/scalevariations/scalevariationtheoryids.yaml b/validphys2/src/validphys/scalevariations/scalevariationtheoryids.yaml
index 6d1af1cff6..98031c3498 100644
--- a/validphys2/src/validphys/scalevariations/scalevariationtheoryids.yaml
+++ b/validphys2/src/validphys/scalevariations/scalevariationtheoryids.yaml
@@ -229,3 +229,35 @@ scale_variations_for:
       (2, 0.5): 607
       (2, 1): 608
       (2, 2): 609
+
+  # N3LO: MHOU + IHOU
+  - theoryid: 1000
+    variations:
+      (0, 0, 0, 0, 0, 0, 0): 1000 # central th
+      (1, 0, 0, 0, 0, 0, 0): 1001 # anomalous dimensions variations
+      (2, 0, 0, 0, 0, 0, 0): 1002
+      (0, 1, 0, 0, 0, 0, 0): 1003
+      (0, 2, 0, 0, 0, 0, 0): 1004
+      (0, 0, 1, 0, 0, 0, 0): 1005
+      (0, 0, 2, 0, 0, 0, 0): 1006
+      (0, 0, 0, 1, 0, 0, 0): 1007
+      (0, 0, 0, 2, 0, 0, 0): 1008
+      (0, 0, 0, 0, 1, 0, 0): 1009
+      (0, 0, 0, 0, 2, 0, 0): 1010
+      (0, 0, 0, 0, 0, 1, 0): 1011
+      (0, 0, 0, 0, 0, 2, 0): 1012
+      (0, 0, 0, 0, 0, 0, 1): 1013
+      (0, 0, 0, 0, 0, 0, 2): 1014
+      (0.5, 1): 1015 # scale variations
+      (2, 1): 1016
+      (0.5, 0.5): 1017
+      (1, 0.5): 1018
+      (2, 0.5): 1019
+      (0.5, 2): 1020
+      (1, 2): 1021
+      (2, 2): 1022
+      (-1, -1): 1023 # DIS coeff functions fact variations
+      (1, 1): 1024
+      # IHOU + MHOU missing prescription
+      (1, 0.5 hadronic): 1025 # As 1018 but DIS from 1000
+      (1, 2 hadronic): 1026 # As 1021 but DIS from 1000
\ No newline at end of file
diff --git a/validphys2/src/validphys/theorycovariance/construction.py b/validphys2/src/validphys/theorycovariance/construction.py
index bf6a676148..4e6513f4ba 100644
--- a/validphys2/src/validphys/theorycovariance/construction.py
+++ b/validphys2/src/validphys/theorycovariance/construction.py
@@ -213,6 +213,18 @@ def covmat_n3lo_singlet(name1, name2, deltas1, deltas2):
         cnt += n_var
     return s_singlet_ad
 
+def covmat_n3lo_fhmv(name1, name2, deltas1, deltas2):
+    """Returns theory covariance sub-matrix for all the
+    FHMV splitting function variations.
+    """
+    s_ad = 0
+    n_var = 2
+    # loop on the 7 splitting functions variations
+    for cnt in range(0,14,2):
+        s_ad += covmat_n3lo_ad(
+            name1, name2, deltas1[cnt : cnt + n_var], deltas2[cnt : cnt + n_var]
+        )
+    return s_ad
 
 def covmat_n3lo_ad(name1, name2, deltas1, deltas2):
     """Returns theory covariance sub-matrix for each of the
@@ -336,6 +348,21 @@ def compute_covs_pt_prescrip(
         # massive coefficient function variations
         s_cf = covmat_3pt(name1, name2, deltas1[-2:], deltas2[-2:])
         s = s_ad + s_cf + s_mhou
+    elif l == 19:
+        s_ad = covmat_n3lo_fhmv(name1, name2, deltas1[:-4], deltas2[:-4])
+        s_mhou = covmat_3pt(name1, name2, deltas1[-4:-2], deltas2[-4:-2])
+        s_cf = covmat_3pt(name1, name2, deltas1[-2:], deltas2[-2:])
+        s = s_ad + s_cf + s_mhou
+    # n3lo full covmat prescriprion
+    elif l == 23:
+        # spit deltas and compose thcovmat
+        # splitting functions variatons
+        s_ad = covmat_n3lo_fhmv(name1, name2, deltas1[:-8], deltas2[:-8])
+        # scale variations
+        s_mhou = covmat_7pt(name1, name2, deltas1[-8:-2], deltas2[-8:-2])
+        # massive coefficient function variations
+        s_cf = covmat_3pt(name1, name2, deltas1[-2:], deltas2[-2:])
+        s = s_ad + s_cf + s_mhou
     return s
 
 
diff --git a/validphys2/src/validphys/theorycovariance/theorycovarianceutils.py b/validphys2/src/validphys/theorycovariance/theorycovarianceutils.py
index 38566397eb..33d0f230a9 100644
--- a/validphys2/src/validphys/theorycovariance/theorycovarianceutils.py
+++ b/validphys2/src/validphys/theorycovariance/theorycovarianceutils.py
@@ -18,10 +18,7 @@ def check_correct_theory_combination_internal(
     """Checks that a valid theory combination corresponding to an existing
     prescription has been inputted"""
     l = len(theoryids)
-    check(
-        l in {3, 5, 7, 9, 62, 64, 66, 70},
-        f"Expecting exactly 3, 5, 7, 9, 62, 64, 66 or 70 theories, but got {l}.",
-    )
+    check(l in {3, 5, 7, 9, 62, 64, 66, 70, 19, 23}, f"Expecting exactly 3, 5, 7, 9, 62, 64, 66, 23, 19 or 70 theories, but got {l}.")
     opts = {"bar", "nobar"}
     xifs = [theoryid.get_description()["XIF"] for theoryid in theoryids]
     xirs = [theoryid.get_description()["XIR"] for theoryid in theoryids]
@@ -109,6 +106,34 @@ def check_correct_theory_combination_internal(
                 "prescription for theory covariance matrix calculation",
             )
         return
+    elif l in [19, 23]:
+        if l == 23:
+            # check Scale variations
+            varied_xifs = [xifs[0]]
+            varied_xirs = [xirs[0]]
+            varied_xifs.extend(xifs[-8:-2])
+            varied_xirs.extend(xirs[-8:-2])
+            correct_xifs = [1.0, 2.0, 0.5, 1.0, 1.0, 2.0, 0.5]
+            correct_xirs = [1.0, 1.0, 1.0, 2.0, 0.5, 2.0, 0.5]
+            check(
+                varied_xifs == correct_xifs and varied_xirs == correct_xirs,
+                "Choice of input theories does not correspond to a valid "
+                "prescription for theory covariance matrix calculation",
+            )
+        elif l == 19:
+            # check Scale variations
+            varied_xifs = [xifs[0]]
+            varied_xirs = [xirs[0]]
+            varied_xifs.extend(xifs[-4:-2])
+            varied_xirs.extend(xirs[-4:-2])
+            correct_xifs = [1.0, 1.0, 1.0]
+            correct_xirs = [1.0, 0.5, 2.0]
+            check(
+                varied_xifs == correct_xifs and varied_xirs == correct_xirs,
+                "Choice of input theories does not correspond to a valid "
+                "prescription for theory covariance matrix calculation",
+            )
+        return
     else:
         correct_xifs = [1.0, 2.0, 0.5, 1.0, 1.0, 2.0, 0.5, 2.0, 0.5]
         correct_xirs = [1.0, 1.0, 1.0, 2.0, 0.5, 2.0, 0.5, 0.5, 2.0]