I agree. You should not be pH-adjusting distilled (or RO) water; and there is no logic in correcting starting pH vs. the pH of solution that goes to the plants. Since salts/ions/ppm levels are so low, theoretically zero, our crude handheld meters can't actually accurately measure the amount of ions in solution, and measurements can vary greatly and not reflect reality. Check and correct pH as your final step.
But be aware that adjusting pH is still largely a matter of luck, with pH of these complex feed mixtures often naturally drifting, microbial growth affecting pH, and pH going in generally overpowered by pH conditions in the medium/soil, besides the meter needing to be calibrated.
All that matters is whether nutes are taken-up by the plant. Better chelated nutes, absorbable over a wider range of media/soil pH, could be better than nutes where you have to adjust pH, which only just adds more salts/ions/ppm. I use AN pH Perfect and am now switching to MegaCrop as base nutes. I add lots of supplements and have poor (≥225 ppm) tap water. But I haven't even checked pH for years and see no deficiencies or excesses.