Minor fix

liquidation.py

@@ -541,7 +541,10 @@ class Liquidation(Workflow, ModelSQL, ModelView):
         return sum(res)
 
     def get_net_payment(self, name):
-        return self.currency.round(self.gross_payments + self.total_deductions)
+        res = (self.gross_payments or 0) - (self.total_deductions or 0)
+        if res:
+            return self.currency.round(res)
+        return 0
 
     def get_currency(self, name):
         return self.company.currency.id

tryton.cfg

@@ -1,5 +1,5 @@
 [tryton]
-version=5.0.5
+version=5.0.6
 depends:
     company
     company_department