In reply to harpreet singh.

An important point is that the method implemented here is called bilinear interpolation. It assumes the fitting data is on a grid and fits a saddle-shaped quadratic patch on each cell. There are other interpolation methods, and I don't know which one you are using in Excel. My suggestion is that you use four data points at (x,y)=(0,0), (0,1), (1,1), and (0,1), and compare the SAS and Excel fits on the interior of the unit square. See https://blogs.sas.com/content/iml/2020/05/18/what-is-bilinear-interpolation.html for the SAS code for that special situation.

If you have additional questions, post them to the SAS Support Communities, where it is easy to post code, images, and have back-and-forth discussions.