IMO topping is best done one or two times a plant. Topping slows growth way down. I've switched to low stress training and supercropping. Look them up. The plant will grow twice as fast and you'll have more tops then you'll ever need. You'll have to remove many when you go to flower to thin the plant out and it will be 3 times the size of the one you topped 25 times.
Low Stress Training (LST) Tutorial - How to Increase Yields for Free! | Grow Weed Easy Super Cropping Marijuana: Simple Secret to Bigger Yields | Grow Weed Easy