...I would hope ABW isn't adding yellow unless you try for a warmer tone than the black inks. If it is I would definitely switch over to QTR since the yellow inks are the least stable.
Aardenburg Imaging tests of, for example, HPR with Epson K3 in ABW mode "Warm" shows at 90 Mlux-hrs a 50% midtone test patch Lab B fade going from 3.0 to 1.8. That is almost certainly the yellow fading.
Stay with QTR for the best longevity and avoid yellow to the extent possible.
Paul