2021.R1(Partitioning): Generated Forecast Values are not as expected

Description:
When running the regression script to validate what the InFORM generated forecasted values should be, they are off as much as $335 in some forecasts.

I tried two different stores that use different projection methods - St. John's and Colony Sq. Both production feeds.

Filled out the spreadsheet to calculate forecasted values with seasonality and trend and each of the forecasts were off by $31 - $335. I want to make sure that this is not a result of the partitioning.

https://docs.google.com/spreadsheets/d/1UON2cQ1epwfkabtidhWNbQz7VY6K7JFB-LDd5YSvmA8/edit#gid=0

Please request View privileges when debugging. Thanks!