You know, computer language differs from the human one not only by syntax, but also by meaning.
Lets symbolically have 3 model zones zones
1: filename(*.doc) and lastchange( 1 month ago)
2: filename("mythe onlyspecialfile.doc")
Do you see the ambiquity of the description ? the 2 possible interpretation ?
you cannot want MD to read your mind...
And, it is related to your zone 6 too.
In computer world the operator AND, according to boolean logic,
means both expressions have to be true.
Does have any of your files all the listed extensions at once ? I highly doubt so.
the OR is what should be used, with meaning of any of options.
Edit: Darlis was less talkative and therefore faster.