Yes. 900ah gross, 450ah net usable.
The battery bank AH setting is likely used to set the time in absorption charging stage. Pretty sure it's wanting the gross AH of the battery bank to calculate from. If the time in absorb cannot be explicitly set, I'd increase the gross battery bank AH to better match.
Vince and Susan
2011 Tiffin Phaeton 40QTH (Cummins ISC/Freightliner)
Flat towing a modified 2005 Jeep (Rubicon Wrangler)
Previously a 2002 Fleetwood Pace Arrow 37A and a 1995 Safari Trek 2830.