99% of fuel injection 4 cyl/6 cyl and 8 cyl (american) autos use the fuelpump in tank (FIT) system, because
The pumps are electric and generate a lotta heat, to produce 40/60 psi to "PUSH" fuel to the engine-safer than "sucking" the fuel !
There is more efficient filtering/ more efficient pressured delivery and better heat dissipation, when submerged in the tank-
It has nothing to do with charging more for the pump troubleshooting--it's for increase fuel mileage/delivery/efficiency--thats just the way it is !
It ain't my fault-