my formulas rely on strict, self-explanatory naming conventions in order to be user-friendly for both Excel novices and experts
I dont see how this will impact on having start - and end - (blank) helper sheets. They do not need to have data on them, and you could even give them a background that says "Not for Use" or something.

Using this method is almost SOP for both more experienced and novice excel users alike, and keeps things simple and clean.

I guess what I'm saying is - I dont have anything more to add than Jeff already has, sorry