House & garden nutrients, PHing water??

The application directions on their website and bottle(s) says to add my cocos a and b, then right after. before I add any additives I need to PH The mix, 5.8-6.2. Then add the rest.
Is this something I NEED to do? Would it be ok to just do what I've always done with other nutrients: mix everything in my water THEN ph, then water.
I could deff ph the way they want if I have to.
Anyone else run H&G Nutrients? What do you guys do with the ph situation?

Bump pls.....anyone?

I use H & G Cocos A B. I follow the directions. Which is ph before adding additives. I initially did not like the brand in flower but I'm starting to enjoy it.

I mix as directed but then the next day add ph down to the whole mix as it drifts up.

I used house and garden soil twice should of learned my lesson from the first time both times soil infested with thrip eggs,I would not recommend any of there products tbh