diff --git a/modules/purchase_trade/service.py b/modules/purchase_trade/service.py
index 6562ea7..c38a5b4 100644
--- a/modules/purchase_trade/service.py
+++ b/modules/purchase_trade/service.py
@@ -334,6 +334,16 @@ class ContractFactory:
         with Transaction().set_context(
                 _purchase_trade_skip_quantity_consistency=True):
             lot.save()
+            logger.info(
+                "CREATE_CONTRACT_LOT_SAVED type=%s line=%s lot=%s qty=%s "
+                "source_lot=%s source_lqt=%s shipment=%s",
+                type_,
+                getattr(line, 'id', None),
+                getattr(lot, 'id', None),
+                getattr(lot, 'lot_quantity', None),
+                getattr(source.get('lot'), 'id', None),
+                getattr(source.get('lqt'), 'id', None),
+                source.get('shipment_origin'))
 
             vlot = source['lot']
             shipment_origin = source.get('shipment_origin')
@@ -342,6 +352,14 @@ class ContractFactory:
             if type_ == 'Purchase':
                 if cls._attach_or_split_source_lot_qt(source, lot, type_):
                     return
+                logger.info(
+                    "CREATE_CONTRACT_LOT_FALLBACK type=%s new_lot=%s "
+                    "source_lot=%s qty=%s shipment=%s",
+                    type_,
+                    getattr(lot, 'id', None),
+                    getattr(vlot, 'id', None),
+                    qt,
+                    shipment_origin)
                 if not lot.updateVirtualPart(qt, shipment_origin, vlot):
                     lot.createVirtualPart(qt, shipment_origin, vlot)
 
@@ -350,6 +368,14 @@ class ContractFactory:
             else:
                 if cls._attach_or_split_source_lot_qt(source, lot, type_):
                     return
+                logger.info(
+                    "CREATE_CONTRACT_LOT_FALLBACK type=%s new_lot=%s "
+                    "source_lot=%s qty=%s shipment=%s",
+                    type_,
+                    getattr(lot, 'id', None),
+                    getattr(vlot, 'id', None),
+                    qt,
+                    shipment_origin)
                 if not vlot.updateVirtualPart(qt, shipment_origin, lot):
                     vlot.createVirtualPart(qt, shipment_origin, lot)
 
@@ -367,12 +393,35 @@ class ContractFactory:
         if not source_lqt:
             source_lqt = cls._find_source_lot_qt(source, type_)
         if not source_lqt:
+            logger.info(
+                "CREATE_CONTRACT_ATTACH_SKIP no source_lqt type=%s "
+                "new_lot=%s source_lot=%s qty=%s shipment=%s",
+                type_,
+                getattr(new_virtual_lot, 'id', None),
+                getattr(source.get('lot'), 'id', None),
+                quantity,
+                source.get('shipment_origin'))
             return False
 
         remaining = cls._normalize_quantity(source_lqt.lot_quantity) - quantity
         if remaining < 0:
+            logger.info(
+                "CREATE_CONTRACT_ATTACH_SKIP insufficient source_lqt=%s "
+                "available=%s qty=%s",
+                getattr(source_lqt, 'id', None),
+                getattr(source_lqt, 'lot_quantity', None),
+                quantity)
             return False
 
+        logger.info(
+            "CREATE_CONTRACT_ATTACH type=%s source_lqt=%s new_lot=%s "
+            "source_lot=%s qty=%s remaining=%s",
+            type_,
+            getattr(source_lqt, 'id', None),
+            getattr(new_virtual_lot, 'id', None),
+            getattr(source.get('lot'), 'id', None),
+            quantity,
+            remaining)
         if remaining:
             matched_lqt = LotQt()
             matched_lqt.lot_p = (
@@ -423,10 +472,34 @@ class ContractFactory:
         cls._add_shipment_domain(domain, source.get('shipment_origin'))
         domain.append(('lot_quantity', '!=', 0))
         lqts = LotQt.search(domain)
+        if not lqts and source.get('shipment_origin'):
+            domain = domain[:2] + [
+                ('lot_quantity', '!=', 0),
+            ]
+            lqts = LotQt.search(domain)
         quantity = cls._normalize_quantity(source['quantity'])
+        for lqt in lqts:
+            if cls._normalize_quantity(lqt.lot_quantity) == quantity:
+                return lqt
         for lqt in lqts:
             if cls._normalize_quantity(lqt.lot_quantity) >= quantity:
                 return lqt
+        logger.info(
+            "CREATE_CONTRACT_FIND_SOURCE_LQT_EMPTY type=%s lot=%s qty=%s "
+            "shipment=%s candidates=%s",
+            type_,
+            getattr(lot, 'id', None),
+            quantity,
+            source.get('shipment_origin'),
+            [
+                (
+                    getattr(lqt, 'id', None),
+                    getattr(lqt, 'lot_quantity', None),
+                    getattr(getattr(lqt, 'lot_p', None), 'id', None),
+                    getattr(getattr(lqt, 'lot_s', None), 'id', None),
+                )
+                for lqt in lqts
+            ])
         return None
 
     @staticmethod