Wedding Cake Autoflower - Barney's Farm

Eight weeks since sprout. Notes from week 8: I'm looking for some theories as to why these two plants are looking so different. Some of it, maybe all of it, is my doing, but I'd like to understand why if more experienced growers have theories. Here's their history. The pics were taken yesterday, at the end of week 8 (week 4 of flower). I treated these plants exactly the same up until the larger one started needing more water (week 3). But I still feed them both the exact nutrient mix. One of the plants showed signs of water stress early in veg. I flushed both (yep, my nute mix was too strong) and the stressed plant recovered, though stunted. Her sister didn't miss a beat. At the end of week six I clumsily topped the same, stressed plant while pulling it out of tent. Again she recovered, but now it gets weird. After that topping, the smaller, stressed plant moved into flower overdrive. Today she's showing dark, fat sugar leaves with lots of trichomes and she seems to be a bit further into flower than her much larger sister with lighter and thinner sugar leaves. My theory is that she's tired of my abuse and decided that she'd best get to flowering and quick. But these plants look so different that I wonder how much was my doing and how much could have possibly been genetics?