Is 1 dec place in 1 case in 10 really significant, given that CH is calculated to be a whole number anyway.

But for players to make sense of your method, differentials would have to be displayed to 2 dec places, unless they recalculate them themselves.

Yes it is significant. A slope of 132 makes a CH of 3 for an index of 2.9 but 4 for 3.0 giving me a whole extra shot which would not happen if differentials were more accurately calculated.

No one needs to make sense of my method. It is not my method. It is WHS method.

I am merely pointing out that WHS method is inaccurate due to the possibility of an accumulation of 8 rounding tolerances.

This inaccuracy would not happen if WHS differentials were two decimal places as that would create a handicap index correct to one decimal place.

The current WHS method will always produce some inaccurate handicap indices (plus or minus 0.1) and some of those will have an inaccurate course handicap (plus or minus one whole shot)

Same method, but more accurate arithmetic, would improve the WHS.