Hmm... yea. It's what's got me wondering, because that's not a nitrogen deficiency. And at 1.2 you shouldn't be seeing tip burn as clearly as that. That tells me the nutes aren't in good balance.
Personally I'd drop the 4/9 approach for next time. It's obviously not a great mix, for whatever reason. What you could do is use a good balanced base feed to 0.9 then some pk to 1.1 - 1.2.. That's usually what I do and it's never steered me wrong. If I had a better camera I'd take pictures of my girls to show you what they look like. In fact If I could find my camera at all I would. You should be able to keep them a lush (but not overly dark) green til the end, and see very little or no tip burn on a good mix at the right strength.
But they look like they're stacking and plumping up, and there's not too much leaf in them, and that's the main thing.
PPK`s FTW....and....Best wayta get over a female`s ta climb out from under a nuther`n....Pussy`s a dime a dozen and NONE of em are worth 9 cents....well.... good one`s are haaaaaard ta find`s all I`m screamin.....now....
Peace.....Freds..........