Yes, that is long-haul vs mid-haul flight. But it's still Japan-US/Canada, so the same greater/general market, just longer distance and crossing a whole of an ocean vs. just 1/2. And typically longer haul flights have lesser availability (are sooner redeemed). But of course, each route has different traffic drivers, booking timelines by customers, etc. YVR is likely a less popular destination, so it may very well have better availability - as it does, if still dates such as Sept 7 are open.