Thank you very much for that straight up answer. I'm beginning to wonder if you'd be farther ahead by either:

Using a single nute product, measuring PPM and topping off with that one nute as you go. Adjust pH only.

OR

Using a blended nute mix and ONLY adjusting pH. After you go through X gallons of added RO water, change out the whole deal and start with fresh, balanced nute mix.