Big difference in cam specs for dynamic compression?

Ah now I understand thanks... I guess that's the problem I didn't calculate the numbers I just read them off the cam card on their website. I also now see the dynamic CR calculator says to use the seat-to-seat timing values. Using that spec my current setup is at 7.8:1 does that sound right (I'm at 5500' elevation)? Then swapping to the 268* cam it drops down to 7.5:1 do you think that would make any difference in lower octane tolerance?