The reward estimate should be more accurate now and provides more info.

Rounds are now assigned selection odds based on their hashrate relative to total raffle hashrate.

This means that the more you donate the more often your round wins.

If you are in the VIP Donor round which has a minimum of 10kH/s donation to enter you will increase the odds of the VIP Donor round being selected by donating more hashrate while remaining in that round.

So go hero mode and send more of your HR to the raffle, just remember to keep a share in the p2pool pplns window ;)