I don't use Globals, I use shared, but I wouldn't think that there is much of difference. Since the formulas look right, the only thing comes to mind is if there are suppressed records or multiple records.
I am assuming that the record changes every page...if it associated with a group that is causing the report to generate a new page, perhaps you can move your formula from the page header to the group header as maybe there is some interaction there. I have tried striping a page, and oddly enough do not get consistent results, so I wonder about formulas in the page header section.
Hope some of this helped