Hi, May I suggest a new group of parameters called "Keep (4.5)" which is exactly the complement of the "Remove (5)" group. Or add a Not "Remove" checkbox.
Reasoning:
Many times I need to keep letters from the start of the end with an exact number of letters, like the first 5 or the last 3. All suggestions in the forum refers to RegEx. which is not easy to modify to match your case. Groups are easier to deal with and understand.
Thanks for a great tool.
BTW. Some of my non-computer friends call it the "Airplane instruments panel". I like the control it gives me.