Hi, yes, the PCU (MFS) knows about the Memory Status of the MS. If memory is full, then the IR is not used.
I don’t know how you know whether the retransmission is using LA or IR in your traces… It is not explicitly stated…
As long as radio quality doesn’t degrade, the retransmission is done on the same MCS. With IR or without IR, it is the same, in this case.
Did you check the MEAN BEP and CV BEP ? Is there a degradation when data are retransmitted ?