My problem is that the calculation is automatic when you validate a form about holidays, in this form you can choose days of holidays or hours of holidays, when is validated , this info (days or hours) are accumulated in other fields. But in the field of hours, when hours are > 7.5 the days must be substracted 1, but this only works in one user.

Hi,

You can add special field in manager that will check when your calculation is done.

For example: in manager view add new field boolean Is special manager? if it is check then you have to subtract 1 in other case you have to do other calculation as per your requirement.

hope above will help you.