bitgo_ben (presumably Ben Davenport) stated that there is no quantisation to KB in Bitcoin Core for fee calculation. Currently bitcoinj/ MultiBit is doing this (i.e. rounding up the tx size to multiples of 1000 bytes).
For instance look at Wallet#calculateFee, lines 4573, 4574
If this is correct then calculated fees could be lower without (particularly) affecting relaying/speed of confirmation.
In a comment in this thread: https://www.reddit.com/r/Bitcoin/comments/3vj556/serviceswallets_with_00001_fee/
bitgo_ben (presumably Ben Davenport) stated that there is no quantisation to KB in Bitcoin Core for fee calculation. Currently bitcoinj/ MultiBit is doing this (i.e. rounding up the tx size to multiples of 1000 bytes). For instance look at Wallet#calculateFee, lines 4573, 4574
If this is correct then calculated fees could be lower without (particularly) affecting relaying/speed of confirmation.
Needs investigating / corroboration.