Balance is measured in money. If your base currency is $, then the balance is $. But SL and TP are price levels, like 1.23456. There are some other options, like "Fixed pips", which converts the input value into price level by adding it to Ask or Bid. The thing here is that it's not only the SL level, there is also a lot size. So I think that you want to set SL where it will lise X money with the lot size that is used.
There is the opposite option available, when you calculate the lot size knowing SL - all these Risk % options in Volume mode. I have to think about the thing you want to do, I'm not sure if it's logically possible to add it as an option. The other question is - do you really want to have such a dynamic SL? Otherwise you can try some calculations. You have something like 1000$, the idea is how to convert this into something like 10 (pips) or 0.0010 (price fraction)