Some (dare I write, I will, likely all) comic book collectors, including me, prefer comic books with white pages. Having said that, I will not pay much more for, to use your example, a CGC designated white-paged copy of ASM 135 9.8 than a copy identified as having off-white pages (or one reportedly having ow-w pages). How much more, $100 (because it reads "White Pages" on the slab which looks very nice).
My reason for this is that CGC has, in my experience, never been consistent with this designation. For example, I have submitted comic books that CGC has identified as having ow-w pages when they have white pages. Conversely, comic books that have, in my view, ow-w pages have been identified as having white pages. It is, if you will, the luck of the draw. Further, over the years many posters have noted, for example, that a comic book initially identified as having ow-w pages was cracked out of the CGC case, perhaps pressed, resubmitted and received a designation of white pages.
I likely provided more information than you care for and, of course, can only note my willingness to pay more for a 9.8 white- paged copy of ASM 135. Perhaps other collectors will pay much more than I for such a copy.