For example author payout is 10$.

Goal is to give you a payout of 50% SBD and 50% SP.

So you get 5$ worth in SBD and 5$ worth in SP.

Or: 5 SBD and 5$/ 3$perSP = 1,66SP.

Or for absolute amounts 75% in SBD and 25% in SP.

A year back you would get 1 SBD and 5 steem(power), when the price was at 20cents.