Is there a limit to how many or much credit can be applied to Lyft rides?

I had a similar issue yesterday. I decided to hail a Lyft ride (which I rarely do) & many of the credits weren't used. It seems like only the 1.50+ credits were applied, but I ended up getting charged over $12 even though I had enough credits to cover most of it. There were a bunch of credits less than 1.50 that weren't applied. In addition it would be nice to be able to see the total credits in one amount without having to use a calculator.