Hi
It is my understanding that the latency adjustments in BIAB are just concerned with the screen display staying in sync with what you hear.

The actual latency the time taken to play a note on you keyboard and hear it, depend on the time it takes the computer and the software to make the sound, this round trip time is your heard latency. This can only be affected by playing with buffer times.
The smaller the buffer the less delay but the more stutter from buffer overflow.
Note, even Asio drivers normally have a buffer setting.
Finding the sweet spot for your set up can be a bit pains taking.
Buffer size is often set high to prevent audio stuttering particularly if your pc is doing a lot of stuff in the back ground like internet , anti virus programs, pretty screen effects, so keep all background task to a min and make an exception for BIAB in your AV this should allow you to lower your buffers for less latency.
Just my thoughts
Mike

BIAB2021 UltraPlus,AsusN55S1Tbssd, W10/64,Akai EIEpro
Yamaha CVP405,SquireStrat, CoolsoftVMidSynth
Novatation Impulse61 Ctr kbd, Cwalk blab Kontakt

http://mikesmusic.byethost16.com/