It'll be decreasing until ICO ends. It's normal because more and more BTC investing in fixed amount of waves (85M)

Not sure if the bonuses have been calculated and paid out already, otherwise you need to wait until the ICO is over. That is, if you invest 1BTC it is currently calculated as 1.1 BTC (10%).

Probably after the ico has ended. Because they don't know yet how manny will participate in the bonus. Obviously.
Edit: the 10% bonus is included in your total amount of Waves.