"My lesson learned is that I should never color in before I leave the tables. In the future, I will walk away with my chips, cash them in and then rebuy in at the next table."

I do that, but sometimes the supervisor walks over and says how much they leave with. It's a guess but they write something down. What I do is put higher value chips in my pocket , mostly during dealer change. Then color in some. Also you can take a bathroom break and hold your seat. Then comeback and leave. Extra time adds up. Have you ever read Comp City. Lots of tips in there, but they are mostly basic common sense.
Barry