diff --git a/Elwig/Helpers/Billing/Billing.cs b/Elwig/Helpers/Billing/Billing.cs
index 6b6a81d..545367b 100644
--- a/Elwig/Helpers/Billing/Billing.cs
+++ b/Elwig/Helpers/Billing/Billing.cs
@@ -55,7 +55,7 @@ namespace Elwig.Helpers.Billing {
                              COALESCE(LENGTH(attributes), 0) ASC, attribute_prio DESC, COALESCE(attributes, '~'),
                              kmw DESC, lsnr, dpnr
                     """;
-                var reader = await cmd.ExecuteReaderAsync();
+                using var reader = await cmd.ExecuteReaderAsync();
                 while (await reader.ReadAsync()) {
                     deliveries.Add((
                         reader.GetInt32(0), reader.GetInt32(1), reader.GetInt32(2), reader.GetString(3), reader.GetInt32(4),
@@ -125,7 +125,81 @@ namespace Elwig.Helpers.Billing {
                 await cmd.ExecuteNonQueryAsync();
             }
 
-            // TODO add second round to avoid under deliveries
+            if (!avoidUnderDeliveries)
+                return;
+
+            var underDeliveries = new Dictionary<(int, string), int>();
+            using (var cmd = cnx.CreateCommand()) {
+                cmd.CommandText = $"""
+                    SELECT c.mgnr, c.bin, COALESCE(p.weight, 0) - c.min_kg AS diff
+                    FROM v_area_commitment_bin c
+                        LEFT JOIN v_payment_bin p ON (p.year, p.mgnr, p.bin) = (c.year, c.mgnr, c.bin)
+                    WHERE c.year = {Year} AND LENGTH(c.bin) = 2 AND diff < 0
+                    """;
+                using var reader = await cmd.ExecuteReaderAsync();
+                while (await reader.ReadAsync()) {
+                    underDeliveries[(reader.GetInt32(0), reader.GetString(1))] = reader.GetInt32(2);
+                }
+            }
+
+            var fittingBins = new Dictionary<(int, string), int>();
+            using (var cmd = cnx.CreateCommand()) {
+                cmd.CommandText = $"""
+                    SELECT c.mgnr, c.bin, COALESCE(p.weight, 0) - c.min_kg AS diff
+                    FROM v_area_commitment_bin c
+                        LEFT JOIN v_payment_bin p ON (p.year, p.mgnr, p.bin) = (c.year, c.mgnr, c.bin)
+                    WHERE c.year = {Year} AND LENGTH(c.bin) = 3 AND diff > 0
+                    """;
+                using var reader = await cmd.ExecuteReaderAsync();
+                while (await reader.ReadAsync()) {
+                    fittingBins[(reader.GetInt32(0), reader.GetString(1))] = reader.GetInt32(2);
+                }
+            }
+
+            foreach (var item in fittingBins) {
+                var mgnr = item.Key.Item1;
+                var id = item.Key.Item2[..2];
+                var attr = item.Key.Item2[2..];
+                var available = item.Value;
+                var needed = -underDeliveries.GetValueOrDefault((mgnr, id), 0);
+                if (needed <= 0) continue;
+
+                var fittingDeliveries = new List<(int, int, int, int)>();
+                using (var cmd = cnx.CreateCommand()) {
+                    cmd.CommandText = $"""
+                        SELECT d.did, d.dpnr, d.weight, b.value
+                        FROM v_delivery d
+                            JOIN delivery_part_bin b ON (b.year, b.did, b.dpnr) = (d.year, d.did, d.dpnr) AND b.discr = '{attr}'
+                        WHERE d.year = {Year} AND mgnr = {mgnr} AND sortid = '{id}' AND attributes = '{attr}'
+                        ORDER BY kmw ASC, lsnr DESC, d.dpnr DESC
+                        """;
+                    using var reader = await cmd.ExecuteReaderAsync();
+                    while (await reader.ReadAsync()) {
+                        fittingDeliveries.Add((
+                            reader.GetInt32(0), reader.GetInt32(1), reader.GetInt32(2), reader.GetInt32(3)
+                        ));
+                    }
+                }
+
+                var changes = new List<(int, int, int, int)>();
+                foreach (var (did, dpnr, _, w) in fittingDeliveries) {
+                    int v = Math.Min(needed, w);
+                    needed -= v;
+                    changes.Add((did, dpnr, 1, v));
+                    changes.Add((did, dpnr, 2, w - v));
+                    if (needed == 0) break;
+                }
+
+                using (var cmd = cnx.CreateCommand()) {
+                    cmd.CommandText = $"""
+                        INSERT INTO delivery_part_bin (year, did, dpnr, binnr, discr, value)
+                        VALUES {string.Join(",\n       ", changes.Select(i => $"({Year}, {i.Item1}, {i.Item2}, {i.Item3}, '', {i.Item4})"))}
+                        ON CONFLICT DO UPDATE
+                        SET value = excluded.value
+                        """;
+                    await cmd.ExecuteNonQueryAsync();
+                }
+            }
         }
     }
 }
diff --git a/Elwig/Windows/SeasonFinishWindow.xaml b/Elwig/Windows/SeasonFinishWindow.xaml
index b338edc..6f4e2f4 100644
--- a/Elwig/Windows/SeasonFinishWindow.xaml
+++ b/Elwig/Windows/SeasonFinishWindow.xaml
@@ -29,7 +29,7 @@
                 Margin="50,80,0,0"/>
         <CheckBox x:Name="AllowAttrIntoLowerBinsInput" Content="Erlauben Lieferungen auch auf (konfigurierte) &quot;schlechtere&quot; Flächenbindungen aufzuteilen" IsChecked="True"
                   VerticalAlignment="Top" HorizontalAlignment="Left" Margin="255,68,0,0"/>
-        <CheckBox x:Name="AvoidUnderDeliveriesInput" Content="Unterlieferungen durch Abzug bei &quot;besseren&quot; Flächenbindungen vermeiden" IsEnabled="False"
+        <CheckBox x:Name="AvoidUnderDeliveriesInput" Content="Unterlieferungen durch Abzug bei &quot;besseren&quot; Flächenbindungen vermeiden" IsChecked="True"
                   VerticalAlignment="Top" HorizontalAlignment="Left" Margin="255,88,0,0"/>
         <CheckBox x:Name="HonorGebundenInput" Margin="255,108,0,0" VerticalAlignment="Top">
             <TextBlock>Bei Lieferungen das Feld <Italic>Gebunden</Italic> berücksichtigen</TextBlock>