I get so confused reading all this stuff. ISTR reading at one point that the tracking circuit in Absorb just did not track MPP anymore, but found the voltage (higher below the knee) that "met the demand" for the buck converter. The buck converter stays "in balance."
If you ran some extra 12v things while in Float, the solar amps, via buck converter, would crank up to meet the demand, but the controller will remain in Float. I have seen that with my MPPT in the afternoon when the batts are nearly full and I run something 12v.
For the amps to crank up with the output watts the same, the voltage must go back down--back up the IV curve towards the knee. So did the "tracker" do that change in voltage to meet the demand or what did? I have no clue. It is all magic black box stuff it might be better not to ask about :)