We're not on the same page, guys. We need the same software and manuals and need to be talking about the same drive if we're going to figure out incongruities.
I have DriveExecutive version 4.01, which is a couple of years old so it won't have a database for a new PowerFlex 400.
I have the 22C-UM001 User Manual that I downloaded just three days ago. It's dated October 2006 and includes information about PowerFlex 400 drives up to firmware revision 5.0.
Get that user manual and look at the organization of parameters on the first few pages of Chapter 3. There's not an unbroken linear list of parameters.
Instead there are groups; "b" parameters for Basic Display, "p" parameters for Basic Programming, "t" for Terminal Block parameters, "c" for Communications, and so on.
This block of "missing" parameters between 254 and 301 is just the numbering gap between the Aux Relay Card parameters that end at r254 and the Advanced Display parameters that begin at a301.