I think they are connected - unless I got seat shifted for another reason. I booked a wheelchair service earlier this year for the outbound of a return trip as I was recovering from an injury - but didn't book anything for the return a week later as I was hoping I would be off the crutches by then, but when booking the assistance I noticed I got moved out of the exit row for the assistance free return leg, and couldn't reselect the exit row seat even though it was still showing as available.