I’ve not ever used the input transformer, but… being interested in it’s future potential I checked out the documentation and I think it can be done. Firstly, I’ll take your word for it’s range restriction even during calculations, didn’t see anything about that in the docs.
Anyway, it seems to have 4 modules, so it can do 4 independent operations on the incoming midi. I’m thinking along the lines of splitting up your calculation into 2 or 4 calculations. For example,
a) If input > 63 then output = ( value - 63 ) * 1.5 + 63
b) if input <= 63 then output = 63 - (63 - value ) * 1.5
Hmm, that might do it, only using 2 modules.
Well, like I said, I’ve only just read the documentation so I could be barking up the wrong tree!! Hope this helps.