diff --git a/app/routers/practices.py b/app/routers/practices.py
index 1baa2b7..6706b33 100644
--- a/app/routers/practices.py
+++ b/app/routers/practices.py
@@ -62,8 +62,25 @@ def _compute_gate_check(practice: RemissionPractice) -> GateCheckResult:
     rules = practice.schema_snapshot.get("gate_rules", {}) or {}
     sections = practice.schema_snapshot.get("sections", []) or []
 
-    iva_ordinario_only_taxable = rules.get("iva_ordinario_imponibile_only", True)
-    use_taxable_only = (practice.iva_regime == "ORDINARIO" and iva_ordinario_only_taxable)
+    # Base di calcolo ammissibile configurata per il bando:
+    # - "imponibile_always"          -> sempre imponibile
+    # - "imponibile_only_ordinario"  -> imponibile se regime ordinario, totale altrimenti
+    # - "totale_always"              -> sempre totale
+    # Default: imponibile_only_ordinario (comportamento foglio excel originale)
+    amount_basis = rules.get("amount_basis")
+    if not amount_basis:
+        # backward compat: se c'era il vecchio flag booleano
+        if rules.get("iva_ordinario_imponibile_only", True):
+            amount_basis = "imponibile_only_ordinario"
+        else:
+            amount_basis = "totale_always"
+
+    if amount_basis == "imponibile_always":
+        use_taxable_only = True
+    elif amount_basis == "totale_always":
+        use_taxable_only = False
+    else:  # imponibile_only_ordinario
+        use_taxable_only = (practice.iva_regime == "ORDINARIO")
 
     per_category_declared = {}
     per_category_verified = {}
@@ -192,7 +209,9 @@ def _compute_gate_check(practice: RemissionPractice) -> GateCheckResult:
             "amount_erogato": float(amt_erogato),
             "any_verified": any_verified,
             "all_verified": all_verified,
-            "residuo_da_restituire": float(max(amt_erogato - Decimal(str(remission_due)), Decimal("0")))
+            "residuo_da_restituire": float(max(amt_erogato - Decimal(str(remission_due)), Decimal("0"))),
+            "amount_basis": amount_basis,
+            "use_taxable_only": use_taxable_only
         }
     )