Updating 10.0 M030 to M040

[ptc-4790977]

I've updated our test instance of PDMLink 10.0 M030 to M040 using the PSI. According to the Windchill Installation and Configuration - Update Existing Installation Guide on page 33 it says that the database user name must be different. Why does the name need to be different, why can't I use the existing database user?

Thanks,
Derek