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You deleted my example; that may be the source of your confusion…

Here, look at it in fixed-width font, with some emphasis:


  0xffffffffffffffffffffffffffff0000
  0x000000000000000000000000000f0000


See how they have the same number of trailing zeroes?  For any target you choose, either both will match it or neither will.  Yet these two numbers are not equal.  Therefore difficulty is creates a partial order on block hashes.  On the other hand "less than" is a total order on block hashes.