Was running a pretty aggressive calorie deficit early on. Lost plenty of weight that way, but hit a wall just as month three began. Eased that deficit down to something more moderate after that, and the weight started coming off again steadily, just in smaller increments day to day. My best guess is the real key is hitting your protein targets while still holding some kind of deficit. That's at least what's worked for me so far.
Running too aggressive a deficit for too long seems to make the body react oddly. Probably interprets it as a genuine shortage and starts clinging harder to whatever energy stores it has.
Currently running a weekly combination of both tirz and reta, planning to shift the balance between the two slightly next week, less of one, more of the other.