I wrote:
The story claims that Mel used indexing.
OK, correcting myself, the story said that he did indexing by modifying
an instruction rather than using the hardware indexing feature. But
presumably he did this because it was more efficient in the cited
example. In any cases where using the hardware indexing feature was
more efficient, he would have used it.
The point of the story is not "Mel's too old and set in his ways to
use new features." The point is "Mel is an expert on every aspect of
the machine, and knows the best techniques for using it."