Yeah, we will try to get the ranking right first... then we will try to guess ratio between systems. I don't think we will ever be able to predict sale numbers this way.
Also, current formula is only based on 5 days of data in March. So I fully expect to twist it again when April NPD numbers arrive.
We can say the first real prediction from this tool will be for May NPD (that is if we have April results soon enough so I can change the formula in time to have updated numbers...)