Hi Njabulo,
It is not possible to configure the Summary tab on the Results page. You can move graphs around on the page, but it is not possible to change the variables that appear in the Metrics table or to add and remove graphs:
samrepo.nrelcloud.org/help/summary.html
You can use the Data Tables tab to see all available metrics and outputs in a table.
SAM's Merchant Plant financial model does not report a payback period. For these projects, the key metrics are net present value, internal rate of return, and size of debt.
Best regards,
Paul.