Guile- did you read this post? This is some good intuition here because it is correct. Hormone replacement does cause supression of its production as well as a cascade of other effects.If this works like steroids, perhaps there might be the same problem where natural production of some of these hormones might slow down or stop?
I wonder why you chose to throw so many different auxins together? Why not pick max 1 auxin and 1 cytokinin? One reason that you see no more than 2 hormones in the literature is because they're trying different orders of magnitudes- say 100:1 auxin:cytokinin to 1:100 auxin:cytokinin. In fact I read that is what is suggested for "homework" in the discussion of many of these tests. The ANOVA tests have no more than 3 hormones. Perhaps cytokinin, auxin, and giberellin. Here is a well thought out ANOVA test for cannabis and various hormones:
http://www.ib.uj.edu.pl/abc/pdf/47_2/145-151.pdf
useless to you, i know, but I do tissue culture so I get a feel for this stuff. Also many of these hormones are finicky in solution, IAA being the most finicky, so your cocktail has probably just trashed your IAA anyways. Many others require special methods for dissolving in solution and keeping them stable.