Hi Arman,
These inputs are described in the "Metering and Billing Definitions" section of the "Electricity Rates" Help topic:
samrepo.nrelcloud.org/help/electricity_rates.htm.
When you check
Roll over net excess compensation to future bills, SAM credits the month that follows the month you choose for
Month for end of true-up period with excess kWh generated in the end of true-up month. If you do not check the roll-over option, SAM applies those kWh to the end of true-up period month.
For net energy metering, SAM calculates excess generation based on the total generation and total load over the month. For net billing, SAM calculates excess generation in each time step.
For net energy metering with $ credits, the $ credit earned in a given month is applied to the following month. For net billing, the credit is applied to the current month's bill, and may cause the bill to be negative, i.e., treated as a payment to the system owner.
Best regards,
Paul.