Anyone who is using putting prediction needs to be aware how WGT 'mix and match' the subjective description of greenspeed (i.e. 'fast', 'very fast', 'championship'...e.t.c...) and the stimp.
So you might get 'very fast 11' which most of us are used to, but you might also get 'very fast 10'.
What this means in terms of your prediction is that the multiplying factor and the reference grid become 2 seperate variables so:
Very fast 10 - multiplier 0.9 referencing a 21 inch grid
Very fast 11 - multiplier 0.85 referencing a 21 inch grid
Fast 10 - multiplier 0.95 referencing a 24 inch grid
Very fast 9 - multiplier 0.95 referencing a 21 inch grid
e.t.c.....depending on how you have your putting predictors set up in the first place.
But you really must read your screens and select the appropriate version of your predictor because this has cost me a number of birdies until I only just twigged it in a ready go on Olympic.
I had only made 1 birdie in 4 holes and kept missing by a small margin but consistently short, then I realized what was happening, made the adjustments and proceeded to rattle in birdies for the last remaining 5 holes!!
Might just make my money back this time, but a lesson learned in to the subtle nature of the game conditions - they really are a wiley old fox aren't they WGT, but not as wiley as deena, lols!!