Hey IYP! A lot of people do things differently. It just goes about how you would like to do it. I was adviced from my old pup to skip T4 and T5. I put in T4 anyways, and that helped me lots. T5 was accidentally put in a few times which irritated me. Going from T4 to T5, or T5 to T6 did not really make much of a plunder difference. With T7 now out, I was already lcbc so I could not tell the plunder difference. When upgrading, with Cat Cafes at your hand, I would just skip to T7 to save money and time in the future.