:smoking: chugging along nicely Al!
Keep in mind mate, that different strains will have different demands, tolerances, quirks etc.,... Don't change nutes, stay on the PB and make adjustments; maybe dial the B down, up the A to lower N and keep plenty of PK around...
Bowing like that isn't always N tox', but I think I see some mild hooking on tips lower down(?) which indicates this girl is a bit bitchy about N, not unusual really,... I'm not 100% on this, and I see the PB rep's point here,.. Again, it may be coming down to individual plant/strain tolerances and such... Guys when it comes to uptake, storage, use/demands, it can make for a much more complicated analysis of cause and effect here, most of which will forever remain a mystery short of lab testing tissue samples!
@Proph -- N-tox' usually doesn't show the tip yellowing/burn
by itself so far as I've seen, but it can be a co-symptom when overall nute burn is happening.... I have never had a solid read on what all causes that exact type of leaf bowing, more than one thing causes it for sure though,....