diff --git a/modules/purchase_trade/pricing.py b/modules/purchase_trade/pricing.py
index f5ef713..b0e8262 100755
--- a/modules/purchase_trade/pricing.py
+++ b/modules/purchase_trade/pricing.py
@@ -1551,10 +1551,12 @@ class Trigger(ModelSQL,ModelView):
     def default_average(cls):
         return True
 
-    @fields.depends('pricing_period')
-    def on_change_with_application_period(self):
-        if not self.application_period and self.pricing_period:
-            return self.pricing_period
+    @fields.depends('pricing_period', 'application_period')
+    def on_change_with_application_period(self):
+        if self.application_period:
+            return self.application_period
+        if self.pricing_period:
+            return self.pricing_period
 
     @fields.depends('from_p', 'from_a', 'application_period')
     def on_change_from_p(self):
@@ -1727,14 +1729,16 @@ class Period(ModelSQL,ModelView):
                             current -= datetime.timedelta(days=7)
 
             elif self.nb_quotation:
-                current = t - datetime.timedelta(days=1)
+                step = 1 if self.nb_quotation > 0 else -1
+                current = t + datetime.timedelta(days=step)
                 while len(dates) < abs(self.nb_quotation):
                     date = datetime.datetime(
                         current.year, current.month, current.day)
                     if self._calendar_is_quote(cal, date):
                         dates.append(date)
-                    current -= datetime.timedelta(days=1)
-                dates.reverse()
+                    current += datetime.timedelta(days=step)
+                if self.nb_quotation < 0:
+                    dates.reverse()
             else:
                 if self.startday == 'before':
                     date_from = t - datetime.timedelta(days=(self.nbds if self.nbds else 0))
diff --git a/modules/purchase_trade/tests/test_module.py b/modules/purchase_trade/tests/test_module.py
index e5dd075..d78c226 100644
--- a/modules/purchase_trade/tests/test_module.py
+++ b/modules/purchase_trade/tests/test_module.py
@@ -3359,13 +3359,13 @@ class PurchaseTradeTestCase(ModuleTestCase):
                 datetime.date(2026, 4, 3),
             ])
 
-    def test_pricing_period_blank_every_uses_available_dates_before_trigger(self):
-        'Blank Every and Nb quotation returns available dates before trigger'
+    def test_pricing_period_blank_every_positive_uses_available_dates_after_trigger(self):
+        'Blank Every and positive Nb quotation returns dates after trigger'
         Period = Pool().get('pricing.period')
         calendar = Mock()
         excluded = {
-            datetime.date(2026, 4, 8),
-            datetime.date(2026, 4, 10),
+            datetime.date(2026, 5, 14),
+            datetime.date(2026, 5, 16),
         }
         calendar.IsQuote = Mock(
             side_effect=lambda date: date.date() not in excluded)
@@ -3374,15 +3374,15 @@ class PurchaseTradeTestCase(ModuleTestCase):
         period.every = None
         period.nb_quotation = 4
 
-        _, _, dates = period.getDates(datetime.date(2026, 4, 13), calendar)
+        _, _, dates = period.getDates(datetime.date(2026, 5, 12), calendar)
 
         self.assertEqual(
             [date.date() for date in dates],
             [
-                datetime.date(2026, 4, 6),
-                datetime.date(2026, 4, 7),
-                datetime.date(2026, 4, 9),
-                datetime.date(2026, 4, 12),
+                datetime.date(2026, 5, 13),
+                datetime.date(2026, 5, 15),
+                datetime.date(2026, 5, 17),
+                datetime.date(2026, 5, 18),
             ])
 
     def test_pricing_period_blank_every_negative_uses_available_dates_before_trigger(self):
@@ -3393,17 +3393,40 @@ class PurchaseTradeTestCase(ModuleTestCase):
         period.every = None
         period.nb_quotation = -4
 
-        _, _, dates = period.getDates(datetime.date(2026, 4, 13))
+        _, _, dates = period.getDates(datetime.date(2026, 5, 12))
 
         self.assertEqual(
             [date.date() for date in dates],
             [
-                datetime.date(2026, 4, 9),
-                datetime.date(2026, 4, 10),
-                datetime.date(2026, 4, 11),
-                datetime.date(2026, 4, 12),
+                datetime.date(2026, 5, 8),
+                datetime.date(2026, 5, 9),
+                datetime.date(2026, 5, 10),
+                datetime.date(2026, 5, 11),
             ])
 
+    def test_pricing_trigger_application_period_defaults_to_pricing_period(self):
+        'application period defaults to pricing period without being cleared'
+        Trigger = Pool().get('pricing.trigger')
+        trigger = Trigger()
+        trigger.pricing_period = Mock(id=21)
+        trigger.application_period = None
+
+        self.assertEqual(
+            trigger.on_change_with_application_period(),
+            trigger.pricing_period)
+
+    def test_pricing_trigger_application_period_keeps_existing_value(self):
+        'application period keeps explicit value when pricing period changes'
+        Trigger = Pool().get('pricing.trigger')
+        application_period = Mock(id=22)
+        trigger = Trigger()
+        trigger.pricing_period = Mock(id=21)
+        trigger.application_period = application_period
+
+        self.assertEqual(
+            trigger.on_change_with_application_period(),
+            application_period)
+
     def test_purchase_line_get_avg_accepts_decimal_matrix_prices(self):
         'purchase pricing averages Decimal matrix prices without float mixing'
         PurchaseLine = Pool().get('purchase.line')