If you reread the original post, you will see that the OP refers to 'month with year', not 'period with year'. It seems you doubt that the OP knows their own requirement.
Not doubting the OP - but he did state that he did not want to follow up with the users...in fact, his response was something to the effect of 'if i started talking to them about that - they would probably avoid me'.
I've analyzed what users need at the company in every project I've done but I also know when to help them by not asking directors and clinicians how they want their date stored. I need to understand what they want to show and how they'd like it shown as well as the business rules. I also like to think ahead to make sure I'm storing data in a way that allows for new future uses. These specific dashboards and charts do not have any component that needs a specific day of a month. Now when data was inserted or modified, that's a different story but not reflected in the visuals. Those timestamps are for my administrative use.
Thanks everyone for sharing your expertise.