Bruce,

IMHO, the posaition of MS is this, if you want the lower price of the upgrade you must stop using the previous and that is why the price for upgrade is lower. If you want to have full license for both versions, don't upgrade, buy the new version at its full price and you be licensed to use both versions. I see the upgrade avenue like trading in your car on a new one.I fyou trade in your current car on a new one then get the new one for less money but you can no longer drive the old car. However, you always have the choice of NOT trading in your current car and paying more for the new which would allow to drive either car.

Just to put out the flames ahead of time I am not making any comment on the fact that the change in the EULA was made without notice of its impact from MS. I am simply explaining how I see the upgrade versus buy new issue.