Custom Roll for Casting Checks in Homebrew Game

In a game I'm in we're using a kind of arcana check for casting in a heavily modified D&D 5th.  We're constantly refining and adjusting to make things slightly easier and a recent refinement is adding caster level to the arcana check (turns out it's really hard to cast successfully when the dice don't cooperate).  The macro I've slapped together worked but with a solution for the refinement inject it stopped working... This is the original macro... [[@{pb}+@{charisma_mod}]] ([[1d(20+@{pb}+@{charisma_mod})]]) This is the modified macro... [[@{pb}+@{charisma_mod}+@{floor(abs((@{level}-2)/2))+1}]] ([[1d(20+@{pb}+@{charisma_mod})+@{floor(abs((@{level}-2)/2))+1}]]) Any help would be appreciated.

Can you describe what you want to appear in chat? Describe any rolls exatly as you would describe them to a player at a face to face table - don't mention anything about roll20 or the character sheet. You dont want the @ part here: @{floor(abs((@{level}-2)/2)) It looks like this part is level/2, rounded down: floor(abs((@{level}-2)/2))+1}. You can eliminate the abs part (which I guess is just in there to handle level 1) like this: floor((@{level}+2)/2)-1 or even just floor(@{level}/2) so for example  [[@{pb}+@{charisma_mod}+floor(@{level}/2)]] If @{level} is a calculated attribute (not a single number, but a sum of several different levels), you might need to put brackets around it, like  [[@{pb}+@{charisma_mod}+floor((@{level})/2)]]

I need the first part of the macro to show the full roll modifier and the second the product of the roll.  I would like if it could be made to be limited to caster class levels, but I don't think Roll20 makes that distinction.