If I have to power up a shed with some SWA the wholesalers charge me double the amount for the cable if the shed is 10m away and not 5m away.
But there is more to it than that. If you are on fixed price for a job (eg new build wiring) and all the materials are supplied for you then you get paid more for a 4 bed house than for a 1 bed flat because it takes more labour time to do the job.
Most people that sew clothes are on piece work.