LowerLimit is the lower limit of the replacement range. UpperLimit is the upper limit of the replacement range. These are variables set by another process which is working.

So how do I:
1) set a selection to between lower & upper limits
2) find & replace within that selection
3) modify UpperLimit where the replacement text is not the same length as the find text.

Note: there are multiple separate find/replaces for the needed application, so in 2 above there are multiple "replaceall"s.