Flowering begins when the plant starts to form flowers. This is biology not bro science.
It takes time for the plants to transition from veg to flowering. Most nutrient companies list a transition period, this period is also commonly listed in botany as the "preflower period" not to be confused with physical preflowers that form when the plant is mature enough.
Counting from flip is an inaccurate way to determine how long your plant is taking to flower because different strains take different amounts of time to transition, and because of the many grow variables which can effect how long this takes. The grow environment and genetic maturity being 2 off the biggest factors on how long the transition takes.
Outdoor growers don't have a timer switch to flip, and you wouldn't say a plant is flowering outside until it began forming flowers. The same thing applies indoors.
The most accurate and detailed breeders absolutely count flower time from when the plants start to show flowers, because otherwise it's just an arbitrary guess.
Edit: To the topic of the thread. I would say yields were low because the plants were small. The auto probably stayed small because you topped. and pruned it more then necessary. The Critical mass should have gotten way bigger if it actually had a 10 week veg time. The combination of topping and pruning likely effected its growth, its also possible there was some sort of other issue that stunned it growth.(watering issue, heat issues, nutrient issues). Any of those things combined with the low wattage of the light will result in a smaller then normal plant and lower yields.