I agree with June7; there's no real way you can do this kind of thing without including the year component. Aside from knowing when the next PM is due, one would think that you'd want to retain a record of each time a PM was done.
The Date handling functions in Access VBA are really powerful and easy to utilize. A number of years ago I wrote a database using the language that VB and VBA was based on, QuickBasic 4.5, and had to do exactly what you're doing here...scheduling, in my case, follow-up home care visits that had variable frequencies. The code for doing this, and taking into account when the projected date went into the next year, if I remember correctly, about three pages of code; in Access, with DateAdd(), it would only take a single line of code!
Linq ;0)>
The problem with making anything foolproof...is that fools are so darn ingenious!
All posts/responses based on Access 2003/2007