Rate override
A rate override pins a specific usage rate for a specific member rate on a specific asset. When an override exists, it replaces the output of the rate modifier on that asset for that scheme — the base rate and the modifier are both ignored.
Overrides are the mechanism for statements like “members on the renter rate pay exactly £300+VAT/hr on the SR22, regardless of anything else”. They are useful when a second asset justifies a different hourly from what the scheme modifier would otherwise produce.
The override is the top of the rate resolution chain: override wins over scheme modifier, which wins over base rate alone.