Blinds vs. ante comparison

[Shandrax]

In Theory of Poker chapter 4 David is talking about adjustments you have to make with high or low ante-structures. He gives a guideline with a 15% rule.

Now to determine the percentage with blinds instead of antes, can I just add small blind and big blind and devide that by 10 for a full ring-game?

For example in a 10/20 game the blind/bet ratio would be exactly 15%.