I looked up and added all the websites for the shops in that building: only Keraglass gives it as no. 1 (also on the shop entrance door), the others as no. 9. So it seems no. 1 is the old number, and no. 9 the new. Cadastre also has address for no. 7, 5, 3 and 1, north of here. I'll add a note to the building