As mentioned in an [answer here](http://meta.stackexchange.com/questions/136537/is-too-old-to-migrate-a-good-reason-not-to-migrate/158330#158330) it should show "too old to migrate" on "off topic" flag of old questions otherwise someone could go on flagging lots of old questions that are/were off-topic only to find it useless because the questions aren't moved even though their flags are deemed helpful.