Question about rating

in variants chess, there are some variants that add a decimal point. Like in spell chess, there used to be +8.1.

This is weird, because i dont think they’;re used 

Do you know the formula to make elo rating? Pretty sure you just don't count the decimal parts of the decimal answers.

Rating is counted up to tenths of a point on the variants server, if you hover over any rating on your variants profile it shows the exact number but the number you see in game is rounded

Haven't seen that, probably for simplicity.

Ty