The multiplier is the factor by which the correct numerical response will be multiplied.

The first unit (Unit 1) has a default multiplier of 1. Thus if the correct numerical response is 5500 and you set W as unit at Unit 1 which has 1 as default multiplier, the correct response is 5500 W.

If you add the unit kW with a multiplier of 0.001, this will add a correct response of 5.5 kW. This means that the answers 5500W or 5.5kW would be marked correct.

Note that the accepted error is also multiplied, so an allowed error of 100W would become an error of 0.1kW.