That is an extremely useful piece of information which is not at all obvious to a (below-)average Perl user, such as myself. I interpreted "days" to mean that I should not expect it to resolve fractional days, or less than a day. But, it sounds like the actual resolution might be seconds.

Is this explicitly mentioned anywhere in the documentation? If not, I think it would be a valuable addition to the -M doc. It would be great if you transferred your knowledge to a patch.