Help making macro for OSR Saving throws

I'm trying to get a sheet ready to run Other Dust, a post apocalyptic OSR game, and I'm lost on how to make the saving throw macros.  The rules are you roll 1d20+situational bonus or penalty and compare it to a number that goes down as you level up. OSR stuff. So what I thought up was making an attribute for the save (ie PE for Physical Effect saves)and doing [[1d20+?{Boon/Bane|0}cs@{PE}]]. Didn't work. I've tried parenthesis, using > and < and queries and nothing is working. I figured an Attribute was the best way to go because the saves are specific to each class. I'd like a macro but also if there's an API solution I can use that too. 

I think the cs/cf only works on the actual roll portion of the macro(ie '1d20cs' but not '1d20+0cs'), but you could LOWER the target number by the amount of the bonus, which would be the same chance of success... example; [[ 1d20cs>[[@{selected|PE}-?{Boon/Bane|0}]] ]] actually, I think that would only work for a Boon.  A Bane (negative modifier) breaks the cs maybe 2 macros, one for bane or one for boon? [[ 1d20cs>[[@{selected|PE} - abs(?{Boon|0}) ]] ]] [[ 1d20cs>[[{@{selected|PE} + abs(?{Bane|0}),0}kh1 ]] ]] or maybe one macro, but 2 prompts? [[ 1d20cs>[[ {@{selected|PE} ?{Bane or Boon?|Boon,-|Bane,+|} abs(?{Mod?|0}),0}kh1 ]] ]] sorry, there's probably a more elegant solution but it's not coming to me immediately. ;-)

Ah! yes, it works perfectly now, thank you Vince!