You can't just look at the exchange rate. US is far larger market than Canada, so the cost to bring PS4 per unit here is cheaper than Canada.
Though, this really is more likely just a store or market trying to capitalize on the high demand.
It's actually cheaper to ship products here through the Port of Vancouver, Delta SuperPort, to the eastern U.S. via rail with the lower CDN dollar, as apposed to shipping through Seattle, L.A. Most Canadian goods are bought with U.S. dollars. The exchange rate plays a large roll in our products.The current rate is expected to be around this level for some time hence the price change. The negative part is when the CDN dollar was above the U.S dollar. The prices for our goods were slow, sometimes nonexistent, in reflection to the exchange rate. Many companies were taking advantage it.