Does having a top-up degree matters when enrolling for a MBA?

It would depend on the school offering the MBA. The 1 year top-up may be overkill, since MBA programs provide the necessary business management courses. You may benefit by asking MBA schools directly. You can do so in the Official MBA Guide, a free service. It will give you a list of schools that satisfy whatever criteria and preferences you specify. Then you can send an email to those schools or even a pre-application describing your top-up plans.