For a form to be used by others, you should restrict your form to the use of formfields, since:
• they can be made to do calculations without the need for macros; and
• content controls require macro and are unusable on Macs.
Also, instead of using checkbox formfields, if you need to use a choice for calculations, you should consider using dropdown formfields.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]