Difference Roman coins RIC I 128 and 548

I wanted to add a picture to this coin, but I found out that I can't see a difference to this coin.
Auction sites too sometimes categorize them as RIC I 128 and sometimes as RIC I 548. But I can't find a visual difference between the two. The visual descriptions in RIC I are also the same.
Does someone have an idea?

Did you look at every small detail and compare them?

All of my roman coins resemble other roman coins that they aren't. By resemble I mean the difference is like the location of an arm--something small like that.