After you receive the last image, so after you leave the image transfer loop, why don’t you do a timer with Get/CAP_FEEDERLOADED, and if TRUE : EnableDS ?
From my point of view, if your code leaves the loop, there are two reasons, first there’s no page in the feeder, or second, the user took too much time to put paper in the feeder and the driver reached its timeout, disabling DS. I assume that you want to restart scanning in the second case.