Dex build fb's so last update all the fbs tht know a thing or too have gone to str build.....
I have tested tho for a t4 fb it seems the str cap is 599 after 599 you lose about 100 hp for some reason for my 187 fb it passed the 599 without the hp loss idk if its due to rank up or whtever or maybe it could be the ratio of str int dex I find the same thing for bl after I dropped dex below about 587 it lost 100 hp.
Str build is proving to be more effective for pvp than dex build to me and I know you're a war guy so I would suggest giving the str build a try