yes its very confusing . like yesterday i invested 7.28 steem on a post in return i got 10.20 steem but they deducted my 1.48 steem and gave me 1.48 steem extra in form of steem power that i cant use it to further promote my posts ,in short if we invest 100 dollar worth steem your 20 percent will be deducted in form of sp . that you cant withdraw for another 13 months. Then how can anyone earn from steemit. infact we are giving our 20 percent money to steemit itself to promote our post , and we need to block that money in form of SP, then how its useful for us.?