I transition into flower after 50 days or so so its a quasi veg/flower period. I noticed my clones go quickly into flower because of their sexual maturity, seeds longer and yeah it varies strain by strain. It makes sense to not go direct to flower like 18 to 12, it short changes the potential energy the plant could receive on the slide down. Ime ramping down from either 18, 17, 16, 15, 14 within a week and then triggering flower by 13.5 or 14 hours for the first three-four weeks of flower gives the plant an extra 38 hours or 3.2 extra days of production that you didn't have before. Plants finish in the same amount of time, you just got to make sure how your strain react and don't mix clones with seeds. Also 13 hrs, 12.5 during weeks 5,6,7,8 will give you an extra 5 days of production. You with me on this?