Figuring a sub par differential?

[flintcreek6412]

OK, so we can all dream.........

But lately I've been carding some rounds at 1 and 3 over par.  It's likely a matter of time before I do actually get a sub par round and it got me to thinking about figuring a handicap, especially for those that often shoot under par.

My home course is a par 72  71.4/135.

When I shoot a 75 I know that my differential is 3.0     75 - 71.4 = 3.6   then   3.6(113/135) = 3.0   Pretty straight forward

But what if I shoot a 69?

69 - 71.4 = -2.4        BUT if I do -2.4(113/135) the differential actually increases to -2.0  ????????

OR do I inverse the slope and do -2.4(135/113) which decreases the differential to -2.9  ?

AND lets confuse it even more........................

Lets say the average of my 10 best is -2

Do I multiply that by .96 thus raising it again or would I now use 1.04 to decrease the number

OK math guys.....let me have it

[iacas]

You do the same: 113/135, and 0.96.

It's the bonus for excellence.

Consider it this way: if you're a 3.0 index you probably shoot 4 over. But you can shoot -2 and be a +1, so you're kind of getting "two" shots on the person.

[flintcreek6412]

Thanks for the info