I had to read that part twice as well. It seems that it's in addition to whatever they are offering 'per bug' - you basically get a 10% bonus on the average of everyone else's payouts.
So for example:
Bug 1 - $2k
Bug 2 - $3k
Bug 3 - $6k
Bug 4 - $1.5k
Bug 5 - $2k + 10% of total commuity average payout as bonus
So for example:
Bug 1 - $2k
Bug 2 - $3k
Bug 3 - $6k
Bug 4 - $1.5k
Bug 5 - $2k + 10% of total commuity average payout as bonus