Does anyone know why (and when) the Jet-708640 model was discontinued? It is the bag model without a remote. The current bag model DC-650, without remote, is 708642BK. The 640 is still being sold at some sites at full price while others indicate that it is discontinued and priced it $100 less. Looking at web pictures of both the 640 & 642 doesn’t indicate the changes that must have been made in the new stock numbers. What improvements did they make?