Well, think of it this way. If you're 20% bf, it's easy to cut. If you're 10% it's harder to get sub 10. The lower the bodyfat, the harder it is to lose bodyfat much less maintain low fat. It's the reason competitors don't typically stay low bf in the offseason. It's the reason i don't go sub 10% until right before a physique show. It's simply easier to gain the weight you need to, and then spend some time cutting. Even at 14 or so percent you'll be able to see which bodyparts are lagging.
Use the search function, tons of threads on clen. What you get out of it is what you put in to it. If you eat 1k above maintenance and take clen, you'll think it's worthless. If you combine with diet and exercise, fat loss will be magnified.