Hi,
For your Second Question, System will confirm the stock in the sales order based on the Availability Check and Checking Rule configuration on OVZ9
If you check for this combination, the Field "CHECK WITHOUT RLT" field will control Automatic Confirmation of Sales order
If the requested delivery date lies within RLT Date are confirmed after RLT Date and If Request Date fall after RLT date , then system assumes that everything is completed and Confirms the stock
you can test by De-activating the check box and note the difference
I am not clear on your first Question
regards,
santosh