Solar panel math for September(ish), October(ish)

September:

Produced 256 units
Exported 48.93 units (@ 9.6739c/unit)
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Used 207.089 units (saving 26.8426c/unit)

Total reduction in power bill = $60.32

October:

Produced 325 units
Exported 72.346 units (@ 9.6739c/unit)
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Used units (saving 26.8426c/unit)

Total reduction in power bill = $67.82