I have seen someone on the forum use 3.60 and 4.10 which makes sense since 1.1 is the first version of the hero at level one, 2.1 is the second time at level one, etc.
You could also add the stars so 4* 3.60 is 4 stars, tier 3, level 60 while 5* 4.10 is 5 stars, tier 4, level 10. Both software geeks and math geeks will understand.