Describe the bug

For a Residential/Commercial case with tiered energy rates and net billing, electricity sales/purchases is incorrect for some time steps.

Example .sam file with Excel calculations: net-billing-tests.zip

Calculations for flat and TOU energy rates are correct.

To Reproduce

1. Open .sam file in above zip archive.
2. Run simulation for "tiered" case and note electricity sales/purchases. See "Tiered" sheet in attached Excel workbook.

Operating System and Version

• SAM 2023.12.17 r1
• Windows 11