Tammie I will try, I could explain it easily in a couple of sentences if we were face to face but let me see if I can do it electronically!
So, when a client leaves a tip for a therapists on a credit card what normally happens in the background is:
Salon owner will pay something like $20 a month for the privilege of having merchant credit account (after they have paid set up fee and either hired or bought terminal).
The cc company in this case obviously takes 3% of all individual transaction paid and they all take circa 30 cents per transaction also.
So lets talk easy figures and use a $100 treatment as an example with a $15 tip on top.
So the way I see it, the owner is paying the set monthly ammount of say $20 for account maint etc. and the 30 cents per transaction so the "problem" arises if the client leaves the tip on the cc and not cash because then the salon owner has to pay more to the cc company as treatment amount is larger now with the cc tip, so instead of paying the credit card company commission on $100 he is paying it on $115, so in this case I guess he is trying to claw it back as he probably gave you the full $15 in the past?
So in a nutshell, instead of the $0.33 which would be the fee for him if a a cash tip was left, the owner then pays 3% on the higher amount (treatment price plus credit card tip) making it $0.45 so it costs him $0.12 cents more for that transaction and that happens each time a client leaves a tip on cc.
Your boss is paying his monthly fees, his 3% of the treatment charges and the say 30 cents per transaction. He is now asking you to pay 'just" the extra 3% charge on the tip amount which in the example above is 12 cents.
Personally I pay my girls whatever the client leaves on the cc and take the hit. If I had a huge staff I can't say I would do the same and I would probably discuss it with them.
Phew that took a while, I hope it all makes sense Tammie.