We have 138 pages for 32 volume.
31 had 162*
30 had 154*
29 had 164*
*Excluding datafiles, cover, colour page, characters description, contents page and page about the recent events.
Including a few pages which Yoshiki made for the full volume release (e.g. there were 4 new pages in vol. 29 if I'm not mistaking).
So we need at least 12 new chapter's pages + 4 new volume's pages to get to "154 pages". Yoshiki can (I hope) make 12 pages in November's chapter, so we may see the new volume in December. Even then he may take 1 month break and release the vol. 32 month later, as he did with vol. 31
Also we need to consider that the vol. 30 had 8 additional pages with character description in the end, so it's possible that we need at least 2 more monthly chapters to get enough pages for the vol. 32. Like 10 in November + 10 in December = 158 chapter's pages, then + 4 volume's pages = 162.
So:
The best-case scenario: volume 32 released in December 2015
The worst-case scenario: volume 32 released in February 2016 (not March because I doubt that Yoshiki need 2 month of his breaks, that will be crazy!)