Accounting standard for "one month ago"

[Robert Graham Merkel]

As previously reported, I'm adding a new type of option for relative
dates.  I'd like to add a relative date for "one month ago".  My
simplistic definition for "one month ago" on 
m/d/yy is (m-1/d/yy) but this
of course poses a slight problem on, say, the 31st of May.

What should we do here, or should I avoid the problem entirely and use
"30 days ago" instead?

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Robert Merkel	                           rgmerk@mira.net

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