Note: you must provide three values at least (levels 1 to 3).
Show results for levels to -
Related forum thread.
And you didn't want to go with "If level equal to 1 then ..., if level equal to ..."?
But, unfortunately, the level-based formula just doesn't want to come?
This script may help...
Plug in the expected result per level, hit "find", and, with a bit of luck, something of use will pop up.