SPI and CPI are calculated based on current budget. If budget is revised but not approved, should SPI be calculated on original or revised budget?

SPI and CPI is calculated based on 'budget at completion'. If budget is revised but not approved then SPI should still be calculated based on orginal budget.

SPI should only be calculated based on the original budget since planned value is based on approved baseline with approved budget, therefore, SPI cannot be calculated on revised budget unless it is approved. Othewise revised budget can be used only for internal progress performance monitoring.

If budget is not revised then SPI and CPI should be calculated on original budget.