Excel Interpolation Function
Double Interpolation Function
MNR - Multivariable nonlinear regression
HTML Table Scraper
Get Your Own Macro
Water Vapor Pressure Function
As the customer will pretest our product by using the free functions and there is no great different between them, the customer should be satisfied with our product.
Accordingly, The only situation for money pay back is "Our customer didn't receive our product mail during 7 working days".