I don't have Excel on my home computer, and for some reason I can't connect to another one through VPN currently, so I can't look what formulas are used on Report sheet. But in general, the formulas use Table and Table Field names, and Named Ranges. So probably a Named Range was the one to confuse you.

Of-course you can post the formula here too (for me it's night currently, so probably I will see it tomorrow morning anyway, but it will be nice to know which formula and which part of it needs to be commented).