It works, i did it before and got an average of 233fps then later took it to a bow shop and they chrono'd the same average speed of 233
That phone is impressive to stop that arrow with less than an inch of penetration. Mine fall to pieces if you swear during a phone call.
I wouldn't think so, there may be some slight change due to humidity levels or wind i supposeI guess it doesn’t matter but does shooting indoor or outdoor make a difference?