Hello all, I recently started IFR training in south Florida. I've had some small issues with my instructor, but I was able to look past them, but in tonights flight and one flight before my instructor has abruptly either pulled back on the yoke, or pushed the nose down. Not gently, but very aggressively. The first time was on the flight earlier this week, and we were not on an IFR flight plan, just a simulated approach, and I understood what he was doing, but I was not a fan of it. On tonights flight, we were on a flight plan and I fell 40 feet below MEA on an approach the first time he did it because I was looking at my TPP to see when I could descend further. The second time was when we were going missed on the approach, and we were enroute to our holding fix, the TPP began to slide off my leg and I looked down to grab it and reposition it. Tonight was the straw that broke the camels back, and I told him to take me back to the airport, that is not the way to train a student, especially without warning me about my altitude. The reason my instructor does these abrupt movements is so we don't get a deviation (altitude bust). My question is: How far off from altitude do we have to be before we are given a deviation?