i think
they sell those refurbished labeled as that
and not as new

the deal is dell used to (dono bout nowadays) do 1-to-1 change, thus leaving them with lots of broken item repairable
so after repairing them, they will be sold of to employee sales as refurbished unit at a lower prices
unscrupulous worker/contact would buy in bulk and sold them off as new

the other company would used sometime to repair the unit, thus no refurbished unit to be had and deal with

this might seem farfetch that dell would just swallow these return unit, repair and sell them off at lower/loss pricing
but this is a good tactic to get good reputation from the masses
the % of issue is gonna be low, so no harm having to absorb the returns loss with more sales due to popular reputations