George,

By valve I mean the nozzle that you clamb the hose to on the plumbing
under the sink. I think it's called an S-Bend over here (I'm from
Down-under).

SQLit,

I don't own a dishwasher yet. I just checked the specs on one
candidate machine and it offers extenions up to 3.6m above the 2.2m
spec. But it also has contrainsts on the installation:
http://www.fisherpaykel.com/pdf_inst...tall_NZGBw.pdf

Page 4 of above shows the installation method, so I think the 5.8m is
really enough to go the distance.

But this dishwasher is the most expensive candidate. The other one is
a whirlpool but there are no lonks to it's spec.

I guess the builder is trying to avoid having to bear the cost of
extending the plumbing.

Mike