Quoted from mikeflan:
Looks like I can adjust the third chute to give two credits for one quarter but not one. Hmm. Not sure if 12.5 cents a game makes sense. Have to think about this one.
Been running into the same issue. I can get it to reward 3, 4, 5 and even 6 credits by following the game adjustment, but minimum is always 2. Can't seem to find the configuration that will only allow one play for one coin. The manual says it is possible, but doesn't really get into detail on how you get there. When these games were released, I suspect it was baked in that only certified techs would most likely be the only people ever getting under the hood, and some of the older manuals are written in that manner.