I believe he is partially correct. The hose that your Tech is speaking of is only 3-4 inches long and is sort of "S" shaped. To replace it IMO requires tearing 90% of the pump apart, and if you are going to do this you may as well replace all the internal seals and so forth (kit is less than $20). The pump has to come out of the car basically and labor is the biggy here.

This is what I dicovered doing the job myself in my garage. Other fellow 500E owners may have some different slants on this?