Yes, the node could be offline for the 12 days, then it will be suspended. After that you would have a week to fix an issue. If the node would be offline or suspended after 30 days, it will be disqualified.
We implemented an /24 subnet rule, this is mean that all nodes behind the same /24 subnet of public IPv4 would be treated as a one big node for uploads (i.e. they would share the same traffic, as if there would be only a one node) and as a separate ones for downloads, repairs and audits. This effectively spread the risk of losing a one node if you have multiple, in that case you will lose only part of the data (the one node from several), not the whole data, as if there would be only one node.
It is also mean, that running more nodes will not give you more income than the node of the same size, so no point to run many nodes on the same disk/pool. It’s useful only if you have a spare HDDs with a free space and do not want to learn or configure RAID with a redundancy.
See also RAID vs No RAID choice