When trying to create the requisition from position management , you will get the screen as shown in the Pic
This document will tell you how to make the Highlighted section Non editable
SuccessFactors Bizx- Recruiting
The permission is not driven via Requisition xml , but in the position fields itself.
For the position which the user is using to create the requisition will have the field "Multiple Incumbents Allowed".
This field is responsible on Number of openings to be editable or not .
If this field value is selected as Yes, which means more than one candidates can be Hired for the requisition . Hence the field will be editable.
If the field value is selected as No, then only one candidate can be Hired and the field will not be Editable
Number of Openings , Position management , KBA , LOD-SF-RCM , Recruiting Management , Problem