Reword phrase to remove ambiguity

I think we should reword the highlighted phrase to say

Unable to power down (ERROR: Account requires 10x the account creation fee in Steem Power. It must have 300 SP before it can power down).

This avoids the parentheses within the parentheses while also eliminating the ambiguity of "(approximately 300 SP)" because this phrase confuses the reader, who may understand it to mean 300 SP is the account creation fee and he would need 3000 SP to power down.