saves having to call time() for each -M, -A, or -C (in addition to making the results equal for different files with the same timestamp).

I'm not quite sure I follow that. If they just returned the timestamp from the files as absolute values, you wouldn't have to call time() at all? And the results of different files with the same timestamps would be the same anyway?

The relative versions allow you to express your problems in problem terms, not in implementation terms. Which is nice when you're writing a perl -e type solution. Think of all the other Perl shortcuts that are designed to let you express your solution in terms of the problem, not in terms of the opcodes.

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[ e d @ h a l l e y . c c ]

Ah; I was thinking the complaint was that they do not provide instantaneous ages in days, not that they don't just give timestamps, so I was giving justifications for having the ages be reported in terms of a fixed timepoint rather than as of the moment -M, etc. is executed, even though it results in oddities such as negative ages for timestamps later than $^T.

bonus points for pointing out missing or extra commas in the above ramble; commas are not my forte