If you don't brew with any other equipment that will use the 'normal' grain absorption, then change the parameter for the 'standard' brewing over to the rate you calculate for your BIAB with batch sparge. This is what I have done for the majority of the brews I perform a sparge on and I do need to switch it back when I use my mash tun set up (the couple of times a year I do brew with it).
Like you, I would prefer to have that setting in the profiles, but in the equipment profile rather than the mash profiles. The mash profiles work for whatever system I brew on, the equipment profiles are more specific to the equipment and process I use.
