Hi Craig
Including seminars in Certifications can produce some unexpected results as in some cases seminar event attendance is required to be kept if it is within the Certification window open date and in some case the attendance is not required to be kept. In some cases a seminar can have more than one date and also not be marked as attended until well after the date of attendance.
What I think you can do to help is to reduce the window open setting and also ensure that seminar attendance is marked as close as possible to when the event occurred.
The Certification documentation is fairly detailed but hard to tell what would be the best settings to suit your case
Regards