Looking good, but how to measure the value in bitcoin? USD is fixed but bitcoin ain't, how will the ICO sales be?
If I could guess when you send BTC to ICO address will require confirmation of the transaction
At the time of your deposit is confirmed then automatically convert values IMHO
That is correct, to make fair. It will be a "time of purchase" scenario.
As soon as you send BTC, the amount of PRO you receive will be calculated based on current market price, and at that specific time.