diff --git a/Elwig/Helpers/Billing/BillingVariant.cs b/Elwig/Helpers/Billing/BillingVariant.cs
index 721356f..7cb41a2 100644
--- a/Elwig/Helpers/Billing/BillingVariant.cs
+++ b/Elwig/Helpers/Billing/BillingVariant.cs
@@ -46,14 +46,14 @@ namespace Elwig.Helpers.Billing {
                            m.mgnr,
                            v.avnr,
                            ROUND(p.amount / POW(10, s.precision - 2)) AS net_amount,
-                           ROUND(lp.amount / POW(10, s.precision - 2)) AS prev_amount,
+                           IIF(lc.amount >= 0, ROUND(lp.amount / POW(10, s.precision - 2)), 0) AS prev_net_amount,
                            IIF(m.buchführend, s.vat_normal, s.vat_flatrate) AS vat,
                            ROUND(IIF({Data.ConsiderTotalPenalty}, COALESCE(b.total_penalty, 0), 0) / POW(10, s.precision - 2)) +
                            ROUND(IIF({Data.ConsiderContractPenalties}, COALESCE(u.total_penalty, 0), 0) / POW(10, 4 - 2)) +
                            ROUND(IIF({Data.ConsiderAutoBusinessShares}, -COALESCE(a.total_amount, 0), 0) / POW(10, s.precision - 2)) +
                            IIF({Data.ConsiderCustomModifiers}, COALESCE(x.amount, 0), 0)
                            AS modifiers,
-                           lc.modifiers AS prev_modifiers
+                           IIF(lc.amount >= 0, lc.modifiers, 0) AS prev_modifiers
                     FROM season s
                         JOIN payment_variant v ON v.year = s.year
                         LEFT JOIN payment_variant l ON l.year = s.year