Sams folks have a long discussion on this - see it here
https://www.thelayoff.com/t/Yxkz6G6
or @OP+Yxkz6G6
2 replies (most recent on top)
Yes, but you have to use it in at least 15 minute chunks.
So of you leave 40 min early you need to use 45 minutes of PPTO.