Originally Posted by jibi
They are taking into account that every user of BlackBerry in the United States would have to take 15-30 minutes to upgrade the OS on their handheld. When they say man-hours, they are simply meaning every single individual user - not actual implementation by their engineers on their systems (it is likely already in place within their network infrastructure). These hours could be concurrent, as a lot of users will likely install the OS update within minutes/hours of it being released.
jibi, that's an excellent point. The man hours is based on work, not duration. If one person was going around upgrading everyone, yep 2 mil hours, if 2 mil at the same time, 1 hour, etc..