I had a sleep study done and it said it took 312 min to REM and 7% for rem. (others were 1-17%, 2-33%, 3-43%) is that okay or not?

Sleep architecture. A lot of this depends on your age for what is considered normal. Long rem latency could be medication related. Also unless < 20 years old 43% n3 is really quite high. This can be seen in people that are very tired and get this deep sleep rebound. N2 usually occupies 50-60% of night in adults (40-50% in teens).. Hope this helps.