I don't think the stampers give a flip about which page they use. If there is a space, they'll use it. Rarely neatly. Often on a random page. And whether or not it is for "Endorsements" or "Visas".

I think the "Endorsements" pages in U.S. passports are intended for the use of the U.S. State Department, not for the country you are visiting. For example, when I was in the military stationed overseas, my family members had no-fee passports. They were just like the standard blue U.S. passports except that they were issued without charging a fee. And on the "Endorsements" page it was stamped "Valid only for travel in conjunction with sponsor's military assignment overseas" or something similar.