Actually, that's the rule from the beginning. If you start to specify that IP is on the second floor and MAC is on the third floor, use MAC addressing.

In principle, since the MAC address is actually valid only in the local area network, although the MAC requirements of different devices are unique, the source and destination MAC in the message will change every time they pass through a routing network segment (the source and destination IP remain the same), so even if the same MAC address exists in different network segments, it actually has no influence. As long as the MAC addresses of the same network segment are not duplicate.