I believe there's no exact values regarding a Bowazon. People always say "full" this and "max" that, neglecting to see the warm fuzzy gray area in between. IMO a Bowazon is one of those characters where the gray area isn't so bad, and it wont make anything worse for your build.
While some people may need that extra safety of points in Vit, others prefer living life on the edge. I'm one of the crazy ones that prefer the latter.
I've got 50 Vit base on my Frosty, and things are going smoothly at level 47. I don't see myself putting any more points there, for that matter. Sure, a Frostmaiden focuses on Cold damage, but more damage/AR overall is all good.