I am trying to replicate my LEAP program's calculation for my transportation stock and flow analysis. Attached is my current excel file. I have noticed a strange behavior - if I choose a constant value for emissions degradation OR for fuel economy degradation, my workbook does a good job of replicating LEAP's emissions results. However. if I plug a constant value for BOTH emissions degradation AND fuel economy degradation, my workbook is a bit off from LEAP's results.

Would you be able to help me find the bug in the spreadsheet, and/or in my LEAP file? I can send my LEAP model if that would be helpful.

Thank you!

Josh