Ok, I'm sure Greg (greolt) or "poppabear" will be along to help with this shortly, but here's my code (which is like Gregs):
Woah!!!!  I don't think my name should be mentioned in the same breath as Poppabear's   
 
I have to ask him the most basic questions.  
 
  And I have never seen that code before.  Never even tried centring routines before.  

Phill  what code are you asking about?  Can you open it in an editor?  Look for an F command and change it to what you want.
If it has none then G31 will use the last used feedrate.  But adding a line should be no problem.
Also see the following two line in Budman's code,
FeedCurrent = GetOemDRO(818) 'Get the current settings    This one near the sart
Code "F" &FeedCurrent  'restore starting feed rate     This one near the end
They restore the feedrate to what it was before running the routine.
Greg