Table Win/Loss is calculated as follows:

Closing Inventory
+ Credits (chips taken back to cage)
+ Drop
- Opening Inventory
- Fills (chips brought to table)
= Win/Loss

This does not account for markers activity, but the concept of marker credits would still apply.

Therefore, when a chipper buys $500 worth of chips at a table and leaves nothing changes to the table hold. Example: Open with $5000, Drop $500 and Close with $4500 assuming no regular play and no fills/credits - what happened? Nothing - $4500 close + $500 Drop - $5000 open = $0 Win/Loss.

Hopefully this answers some questions; otherwise I can answer all your favorite casino accounting questions.

PS - average ranges of table holds are as follows:

BJ - 14% ~ 18% (depending on decks)
CB Stud - 30% ~ 35%
Roulette - 28% ~ 35%
Craps - 22% ~ 28%

A mixed rate of all games around 16% ~ 18% would be acceptable.