Those estimates should be pretty close although the BC may be a bit low. Using your 1500fps and varying the BC up and down from .14 to .22 only makes about a quarter inch difference at 50 yards so if your BC is a little off it won't make that big a difference. Varying the velocity by +/- 150 makes about an inch difference at 50 yards, still not a big difference. Sounds like you should be close enough to start and can fine tune from there.