Block explorer block/transaction sizes dont appear to reflect transaction fees

Looking at transactions and block sizes in Bytes on explorers, and the transaction fees paid, they dont seem to line up properly.

If the base fee is 0.155381 ADA and the variable fee is ~0.000044 ADA, then a transaction included in a block like this of 290 Bytes should not have cost 0.168801 ADA.

Assuming the block header was 0 Bytes, and the whole 290 Byte payload was the transaction:
(290B * 0.000044 ADA) + 0.155381 ADA = 0.168141 ADA

The TX fee was too high by 0.168801 - 0.168141 = 0.000066

Is the transaction fee calculation wrong, or is the block explorer wrong?