First off, apologies if this is already known, but I ran into this just recently.
When I decided to fil my supplies ot my bunker, it was still pretty full, so I spent 30K on supplies and then started a playlist of 16 Madrazo Jobs.
When I was finally done after an hour, I go thte message from Agent 14 and when I checked my bunker supples were full and my value had increased from 308K to 418K or something. Good deal for 30K of supplies.
Might be a one time thing, though.
Again, if this is old news, please delete.
EDIT; It's kinda like the really old trick from Bikers when you disbanded after bing 15K worth of supplies, and then registerd as an MC President when your supplies were empty. I think this trick is more unnoticed as of yet.
EDIT2: Hmm, seems that doing a playlist now SUSPENDS the supply delivery, so if you buy 15K worth of uspplies and you finish the playlist after an hour (depending on how many jobs were in it) supplies will have been consumed, but bought supplies will still be on their way to top off the bunker.
But yeah, probably not a super efficient way of saving money, but can be good for the 25% bunker product manufacturing boosts and/or 2x on certian contact missions.
At least this one seems to be a little hush hush..
EDIT3: THis is on PC, so if this works on Console I don't know yet.