This is not a SU moderation policy, but a network-wide feature and can't be changed per site: Questions older than 60 days can't be migrated, period (another meta.se discussion).
I don't see any real value in this anyway. We also don't migrate questions that might live on SU and close them instead and we answer Unix questions that are not really off-topic, but would be more on topic on U&L.
And both Puppet and Munin can be used in hobby/home environments as well, which would make the question off-topic here.