You might want to this approach. If a user does not understand the form and cannot move out of a field they can become very negative about the form. A possible better approach would be to have a displayed field indicate thing one of the payroll options needs to be selected and when one is selected the message disappears. You should also include some code to verify the payroll type has been completed before the form is saved, printed or closed. You could also make the working time fields locked until the payroll selection has been made.
Disabling (graying-out) form fields with Acrobat 7 and 8 by Thom Parker. It iwas before version XI so the interface for processing the fields is different but the code and form field features are still the same.
Your input appreciated. :-)
That being said, the form is a conversion from having used a Word document in the past.. and people would forget or ignore things we wanted/need them to address. Use of a PDF form is intended to help them to "not forget" and/or "not ignore" specific data fields.
The plan is to send an accompanying 1 page explanation so that expectation will be set before the fact.
Hope all is well & till later,