If you have token mooks, the you won't want to update the sheet. You'll have to update the token. Either way, you can store info on the fly using Plugger to launch TokenMod, ChatSetAttr, etc. The advantage of Plugger in this case is that the downstream command can access the existing rolls of the outer command... Letting you judge the result of the save to determine whether to apply Advantage or Disadvantage. If you need to store the advantage/disadvantage result on the token, you aren't limited to the token bars. If you have something that will write to the GM notes, Fetch can help you read that back when it comes to checking the state.