How to detrmine last pricing used National 9M

[a_gunslinger]

Just acquired an old National 9M. Trying to determine what the price was for a pack. Tried mutiple combinations of coins from .25 up to .50 not luck. I know can I can disassemble to the coin mech but that can be super complicated and wrought with failure for me =^) Hoping to just determine what it was last set for and use that. And hope it wasnt the weird ones that were 0.23 and they gave you 2 pennies back taped to the pack. Had a sticker on it that said $0.40 but couldnt get that to work in any combination.

Any tips appreciated!

Pictures below. Last picture is a restored one from this great video I receied. Deep inside it has the bottom coin mech are levers to set price. Dont want to go there unless I have to - its complex.