[mgsouth]

Not if the additional cost is more than the additional revenue.

Let's assume that without binning you get 20% over cost of manufacturing. If it costs 5% more to bin-check all resistors, and you wind up selling 1% of them for an additional 100% mark-up:

                     No bin          Bin
    Cost to mfg:     $ 1.00       $ 1.00
    Cost to bin:                     .05
                     ------       ------
    Total cost       $ 1.00       $ 1.05

    Base price       $ 1.20       $ 1.188   (99% sold at base)
    Premium price      0.00       $ 0.022   (1% sold at un-binned cost x 2.2)
                     ------       ------
    Total revenue    $ 1.20       $ 1.21
                     ======       ======
    Profit           $ 0.20       $ 0.16