How close is 91 octane in or to 93 octane in US
 

I spoke with the administration that handles the gas quality here, or whatever can't even remember their name, and they said 92.7 is the actual octane of 91 here in Pr.... Wondering if.3 is enough of a difference to cause detonation provided I'm at about ... 13 psi? I'd hate to do a rebuild..