diff --git a/src/base_consist.cpp b/src/base_consist.cpp
index c7fcdec..2005127 100644
--- a/src/base_consist.cpp
+++ b/src/base_consist.cpp
@@ -44,4 +44,8 @@ void BaseConsist::CopyConsistPropertiesFrom(const BaseConsist *src)
 	if (HasBit(src->vehicle_flags, VF_TIMETABLE_STARTED)) SetBit(this->vehicle_flags, VF_TIMETABLE_STARTED);
 	if (HasBit(src->vehicle_flags, VF_AUTOFILL_TIMETABLE)) SetBit(this->vehicle_flags, VF_AUTOFILL_TIMETABLE);
 	if (HasBit(src->vehicle_flags, VF_AUTOFILL_PRES_WAIT_TIME)) SetBit(this->vehicle_flags, VF_AUTOFILL_PRES_WAIT_TIME);
+	if (HasBit(src->vehicle_flags, VF_SERVINT_IS_PERCENT) != HasBit(this->vehicle_flags, VF_SERVINT_IS_PERCENT)) {
+		ToggleBit(this->vehicle_flags, VF_SERVINT_IS_PERCENT);
+	}
+	if (HasBit(src->vehicle_flags, VF_SERVINT_IS_CUSTOM)) SetBit(this->vehicle_flags, VF_SERVINT_IS_CUSTOM);
 }
diff --git a/src/economy.cpp b/src/economy.cpp
index 37a89b3..a3c5836 100644
--- a/src/economy.cpp
+++ b/src/economy.cpp
@@ -431,11 +431,38 @@ void ChangeOwnershipOfCompanyItems(Owner old_owner, Owner new_owner)
 			FreeUnitIDGenerator(VEH_SHIP,  new_owner), FreeUnitIDGenerator(VEH_AIRCRAFT, new_owner)
 		};
 
+		/* Override company settings to new company defaults in case we need to convert them 
+		 * This is required as the CmdChangeServiceInt doesn't copy the supplied value when it is non-custom
+		 */
+		if (new_owner != INVALID_OWNER) {
+			Company *old_company = Company::Get(old_owner);
+			Company *new_company = Company::Get(new_owner);
+
+			old_company->settings.vehicle.servint_aircraft = new_company->settings.vehicle.servint_aircraft;
+			old_company->settings.vehicle.servint_trains = new_company->settings.vehicle.servint_trains;
+			old_company->settings.vehicle.servint_roadveh = new_company->settings.vehicle.servint_roadveh;
+			old_company->settings.vehicle.servint_ships = new_company->settings.vehicle.servint_ships;
+			old_company->settings.vehicle.servint_ispercent = new_company->settings.vehicle.servint_ispercent;
+		}
+
 		Vehicle *v;
 		FOR_ALL_VEHICLES(v) {
 			if (v->owner == old_owner && IsCompanyBuildableVehicleType(v->type)) {
 				assert(new_owner != INVALID_OWNER);
 
+				/* Correct default values of interval settings while maintaining custom set ones 
+				 * This prevents invalid values on mismatching company defaults being accepted (FS#6254)
+				 */
+				if (!v->ServiceIntervalIsCustom()) {
+					Company *new_company = Company::Get(new_owner);
+
+					/* Sending the interval is not needed as the default settings will request the same value.
+					 * However to not rely on that implementation detail we should still send it to prevent bugs when it changes.
+					 */
+					int interval = CompanyServiceInterval(new_company, v->type);
+					DoCommand(v->tile, v->index, interval | (new_company->settings.vehicle.servint_ispercent << 17), DC_EXEC | DC_BANKRUPT, CMD_CHANGE_SERVICE_INT);
+				}
+
 				v->owner = new_owner;
 
 				/* Owner changes, clear cache */