High Compression results and Cranking RPM's

[240sHorTy]

I finished my timing chain job just a couple of days ago and decided to run my compression numbers. Tests come out good per Chilton's and FSM numbers. (Min: 151 Standard: 179 Max Diff: 14 psi) I got between 173 and 176. So very consistent. I also tested my brother's 240 for comparison. Both use similar mileage '95 DE's, so tests 'should' be comparable. But I tested his out and got 182 to 195 psi. I've also checked the archives and found several examples of cars testing to this psi range.

My question(s): I think I've read that these numbers are relative to each other and not car to car? The cranking RPM's listed as spec for the test are 300 rpm's. How much can the cranking RPM affect compression? I would think that anything above the 'standard' would mean that the RPM was a little high, not that the engine seals better than factory specs? And if the RPM's do affect the numbers, than how can we suggest a rebuild below 151 if that could mean the starter is just cranking a little bit slow??

I'm sure some of you have considered this. Maybe someone has a definitive answer? I'm not so much concerned about my engine numbers, but I do wonder about the reason for the discrepancies.

And just so I don't have to answer the 'maybe you are retarded' type ?'s. Both engines were warm and tested w/ all plugs out and dist./fuel pump disabled. And yes, both were a WOT. Minimum 5 cranks per test. So what do you all think??

-Steve