[Orgmode] question about time range calculation

[Detlef Steuer]

Hi,

I've a line like this in my org file
* EABI
  new --> EABI <2007-11-07 Mi 14:29>--<2007-11-07 Mi 14:35>

and would like to add the time difference between both stamps at the 
end.

As I understand the fine manual, C-u C-x C-y does exactly this.

"C-c C-y
    Evaluate a time range by computing the difference between start and end. 
With prefix arg, insert result after the time range (in a table: into the 
following column)."

But: It adds the time difference at point position, not after the time range.

Am I doing something wrong?

Thx
detlef

PS: org-5.13e here