Have you checked the prices? If not, why are you claiming one costs more than the other?
This is what I said:
The links in the OP specified the zing coatings of the top and bottom sheets.
The coating is critical, make sure you're comparing apples to apples when you get pricing.
All I've said was to check the specification of the material to better compare. If one is galvanized and painted, and the other is just painted, the one that is galvanized is worth more.