Is an addition considered major renovation or NC?

Dear all, Our project consists in an existing subway station to which a train station will be added. thre will be a new roof and a new slab of a new floor that will cover both the new rail station and the existing subway station structure. However, the electric and water utilities and the envelope of the existing subway station will not be touched. Does that configure a major renovation or or a new construction? Especially in EAp2, it makes a big difference since for major renovations a 5% reduction is required, whereas for new construction a 10% reduction is required. Thanks