Nothing in the law requires that each month must get its own logbook --
just as nothing in the law requires that we use the recap.
The one-month "rule" is a general practice --
largely because most of the time in most cases that's a handy way to do it.
The recap is a potentially useful tool -- to help us to avoid breaking the 70-hour rule.
A preference, a general practice, or a company rule is one thing, but a legal requirement is quite different.
Best wishes to all,
Doc.