My old bottle(the sturdy generation of 1L containers from AN) claims the ingredients of the 9-18 Hammerhead are Monopotassium phosphate, also known as MKP, which is 0-52-34, and sulphate of potash, also known as potassium sulfate, at (I believe) 0-0-50.
So no nitrogen before.
Given that a lot of people are using the hammerhead/
moab combo for the last two weeks of feeding for the pk boost, this may fuck things up with the new added nitrogen. Because it is pretty important to get your nitrogen ratios correct at the end of flowering.
I believe budboy299 has a formula of how much to add of the two salts I described to duplicate the old hammerhead formula, if you look back a ways in the nutrient subforum.
I for one will not be taking a chance with the new hammerhead with the nitrogen.
Hope this helps clarify.