My 2008 s550 has a sticker that calls for 95!!! octane! If i can only get 93 at the pump do i need an additive

The highest gas I have ever seen is 93 octane. I don't know much, but i do know the higher octane gets better compression in high performance cars, so does that mean I need an additive or should i just get JP4 rocket fuel. I mean if I can't even get the gas at the pump, then why recommend it?!