diff --git a/basicswap/basicswap.py b/basicswap/basicswap.py
index 239109a..f8622c5 100644
--- a/basicswap/basicswap.py
+++ b/basicswap/basicswap.py
@@ -4136,13 +4136,13 @@ class BasicSwap(BaseApp):
             ensure(script_lock_value == expect_sequence, 'sequence mismatch')
         else:
             if offer.lock_type == TxLockTypes.ABS_LOCK_BLOCKS:
-                block_header_from = ci_from.getBlockHeaderAt(bid.created_at)
+                block_header_from = ci_from.getBlockHeaderAt(now)
                 chain_height_at_bid_creation = block_header_from['height']
                 ensure(script_lock_value <= chain_height_at_bid_creation + offer.lock_value + atomic_swap_1.ABS_LOCK_BLOCKS_LEEWAY, 'script lock height too high')
                 ensure(script_lock_value >= chain_height_at_bid_creation + offer.lock_value - atomic_swap_1.ABS_LOCK_BLOCKS_LEEWAY, 'script lock height too low')
             else:
-                ensure(script_lock_value <= bid.created_at + offer.lock_value + atomic_swap_1.INITIATE_TX_TIMEOUT, 'script lock time too high')
-                ensure(script_lock_value >= bid.created_at + offer.lock_value, 'script lock time too low')
+                ensure(script_lock_value <= now + offer.lock_value + atomic_swap_1.INITIATE_TX_TIMEOUT, 'script lock time too high')
+                ensure(script_lock_value >= now + offer.lock_value - atomic_swap_1.ABS_LOCK_TIME_LEEWAY, 'script lock time too low')
 
         ensure(len(scriptvalues[3]) == 40, 'pkhash_refund bad length')
 
diff --git a/basicswap/protocols/atomic_swap_1.py b/basicswap/protocols/atomic_swap_1.py
index 8d9c0a7..62774ae 100644
--- a/basicswap/protocols/atomic_swap_1.py
+++ b/basicswap/protocols/atomic_swap_1.py
@@ -12,6 +12,7 @@ from basicswap.script import (
 )
 
 INITIATE_TX_TIMEOUT = 40 * 60  # TODO: make variable per coin
+ABS_LOCK_TIME_LEEWAY = 10 * 60
 
 
 def buildContractScript(lock_val, secret_hash, pkh_redeem, pkh_refund, op_lock=OpCodes.OP_CHECKSEQUENCEVERIFY):