Advice needed not sure if this is legal

I started this new ice cream job about a month ago and I like it so far but there just something that I don’t get. So I got my second paycheck and I noticed that it said I’m being paid 13.00 hourly. The reason I’m only noticing this now is because the first paycheck I got, it said 15.00 hourly and I already cashed it out. They said they gave me more than I was supposed to be paid and I understood and just gave them the extra money they given me. But now I’m looking at this second paycheck and it says 13.00. Before I accepted this job my boss asked me how much I was expected to be paid, I said $15 hourly and he said ok sounds good. On indeed it says 15-17 hourly. So I confronted him about it and he says that technically I am being paid 15 still. He tried to explain it to me. I worked 35 hours in two weeks. Since I’m getting 13 hourly that would be $455. And the tips that I made which said 69 on the check, would equal to $524. So the tips would pay out the rest of what I’m supposed to be paid by him. If I was being paid $15 by him, it would be $525. But those tips are supplementing what he is supposed to be paying me. He gave me my correct first paycheck too since he messed up the first one, and I’ve noticed that it did the same thing as the second one. Basically he used the tips to cover the rest of the paycheck of what he is supposed to pay me. Isn’t tips supposed to be added on top of the wage he is supposed to pay me? Not used to cover the wage we agreed upon. I live in Alaska and I’m just confused and I’m not sure if what he is doing is right or not.