Word alterations

Is it common to say-
a *giggle* of girls meaning a group of girls giggling?

and

He is a workaholic:he *averages* twelve hours working in the office?

Is *average* commonly used that way

thanks

'Giggle of girls' is not, I think, in common usage, but it has a certain something. It has presumably been invented either by this author (or someone else) as a convenient collective noun.

'Averages' is often used that way (at least in the UK). It is perhaps not the most elegant of uses, but it is very common.