We'd like to explain about the extra bounties meaning here
When our promotion starting,people who complete each step of promotion task could get some corresponding reward
For example:you help to promote this program via facebook,originally you could get 200 coins(just for example amount),and if you're the first 100 replies here,you may get extra 10% reward=200+200*10% total 220 coins
and here is the calculation formula:
first 100 of replies people will has more 10%
first 300 will has more 5%
first 500 will has more 2.5%
If there is any inconvenient understanding before this explanation we apologise