Billing: Fix modifiers with absolute amounts

Elwig/Helpers/Billing/BillingVariant.cs

@@ -232,7 +232,7 @@ namespace Elwig.Helpers.Billing {
                 SET mod_rel = mod_rel + excluded.mod_rel;
 
                 INSERT INTO payment_delivery_part (year, did, dpnr, avnr, net_amount, mod_abs, mod_rel)
-                SELECT d.year, d.did, d.dpnr, {AvNr}, 0, COALESCE(m.abs, 0), COALESCE(m.rel, 0)
+                SELECT d.year, d.did, d.dpnr, {AvNr}, 0, COALESCE(m.abs, 0) * d.weight, COALESCE(m.rel, 0)
                 FROM delivery_part d
                     LEFT JOIN delivery_part_modifier p ON (p.year, p.did, p.dpnr) = (d.year, d.did, d.dpnr)
                     LEFT JOIN modifier m ON (m.year, m.modid) = (d.year, p.modid)