I had no way of knowing this was implemented in a premier appointment as you did not specify this in your initial question.
as I have already said, the numeric range validation you are asking about cannot be done with jquery.
so to answer your question;
"Do you feel that my solution, as described above, will cause problems?"
Yes, because it cant be done that way.
Let me check with Ray to see what he would suggest, I don't know how he implemented the lookup, so I need to check with him. I'll let you know when I have more details.