I was also proactively contacted by my visa agent (www.vietnam-visa.com) 2 days ago about changing 1 year visa letters we had already completed last month to the single entry 30 day (departure date 12/17 Tokyo time since we live here) and they have already issued a new letter in less than 24 hours of responding to them. First time going to Vietnam for a family of 3 including a Chinese wife, so hopefully everything goes smoothly tomorrow. Will update from Danang Intercontinental once settled.