An engine makes power by burning fuel. The more fuel that it can burn [in the correct fuel/air ratio] then the more power it can produce. Geting the fuel in there is the job of cam, exhaust, ports, induction etc. etc.

Raising the compression will increase the efficiency of the burn, but this is offset by the fact that we are limited by the octane rating of the available fuel.
As the compression pressure increases, so too does the likelyhood of detonation, which must be countered by reducing the amount of spark advance.

Retarding the spark, as we know, reduces the maximum amount of power that an engine can produce, so there seems to be a balance, beyond which an increase in compression becomes counterproductive on pump fuel & this seems to be somewhere around the 9.5 - 10.5 to 1 from my observation.

Are you now running this engine on expensive premium fuel?