The B707 had this 25,000/one pack limitation as well.
Recall years ago when enroute at FL350, one pack just quit. No reset possible. Decided to land enroute (9hr flight) due to suspected problems with the remaining pack (there was). Marketing was very upset, but the fleet manager told 'em to back off, pilots had the final authority...period.
Airline involved...SQ, many years ago.
How things have changed over the years.
