first off, i'm terribly skeptical of any 1-part nutrient. how the hell are you going tweak it to get higher relative N in veg and higher PK in flower if there's only one way to run it?
Unless you're a hydro guy, there isn't a lot of tweaking needed for hand-watered container gardening. Your plants need a lot less P and a lot more N than a lot of these 'hydro store' brands supply in their 'bloom' formulas essentially making them useless. A well balanced, complete one part can work exceptionally well from seed to harvest if used correctly.