How does an SCF feed Scope 3 Category 1?

Multiply the SCF by the quantity of service purchased, in the same functional unit. This puts services on the same product-level rung as goods with a PCF. Where no SCF exists, the supplier's corporate footprint divided by its revenue, applied to your spend, is the next rung and is often the practical route for services, which are usually bought by value rather than by unit.