Why does the Sprint Treo Pro get IE Mobile 6 on 15 March?

I LOVE my Palm Treo Pro (see my review) and over the past few weeks my AT&T SIM has spent a majority of the time in it because of the battery life, Exchange functionality, stability, and 3rd party application support. I think it is just about a perfectly sized and designed device and am happy to see it coming to Sprint. It is rather interesting given that the Palm Pre is coming soon on Sprint too, but I think the Pre may be coming later rather than sooner with this March release.

The GSM Treo Pro I bought supports HSDPA while the Sprint Treo Pro supports EV-DO Rev. A. WiFi, GPS, and Bluetooth are still present, as well as everything else found in the GSM Treo Pro. One MAJOR improvement found in the announcement is the line that states, "Treo Pro is the first Palm phone available with Internet Explorer Mobile 6". We were previously told that existing devices couldn't support Internet Explorer Mobile 6, but it seems that those of us with a current Palm Treo Pro should be able to upgrade to this version as well. What the heck is going on here Microsoft?