Instrument overhaul - Are all overhauls created equal?

Today I received the following quotes to overhaul an autopilot DT.
They appear to all be equal except for the price. What am I missing
here??
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We charge $804. Our overhaul is a complete with all bearings replaced
and any worn parts replaced with new, including a new rotor assembly.
One year warranty.

Overhaul Price for S-TEC DGI P/N 6406-14L is $695.00
Overhaul consist of replacement of Bearings, Rotor Assy, and any parts
that do not meet OHC specs. We warrantee our overhauls for one year.

We charge $250 plus shipping to overhaul that instrument. Overhaul
consists of new bearings, rotor, cleaning and all adjustments as well
as run-in. We provide a one year warranty