Is it the same for each style of blade? I was always under the impression you increase it by 3/10ths of a percent for full hollow and decrease by the same for wedges. That is if your are north of the equator, if your south, then.....well I guess your screwed because the formula only works north of the equator.
I always thought the increase was the other way around for the wedge and hollow,, But I do concur on the N and S of the Equator as per reading our AU friends posts