Hey there, GADisneyDad14!
LOL! Yes, this is something that I have read about, but not experienced. Like you, I have read of it going both ways. I suspect that checking into another resort may be a problem for magic bands continuing to work on the 'completed' reservation. However, we will be in the MK area all that last day and into the evening, so we would like access to the lounge, if possible. Things change at WDW all the time, so I was just wondering about recent experiences.
I am contemplating waiting to check into ASSp at the end of the day. As long as we haven't checked into ASSp, I am hoping that there won't be a problem. If we give the luggage to Bell Services to transfer, we would then just head over to ASSp after the
MNSSHP to crash for the night. We are leaving first thing the next morning, so ASSp really is just a bed to sleep in until we head to the airport around 8:00 am.
OTOH, I also think that it is nice to have the room settled before midnight when heading out early in the am. **sigh**
I obsess over details way too much!! LOL
We are staying SL as RPC isn't showing availability for our dates. That is fine, IMO, as this is a whirlwind 4 day visit that will be quite park intensive. We won't use the CL 'lounge' for much more than breakfast or a quick pit stop on occasion. Of course, if RPC would be kind enough to open up with availability, I might just need to switch rooms again, anyway.

LOVE RPC!
Thank you for your insight!