Re-checking Availability

Our company had a similar requirement. We handle the requirement through ABAP code with an enhancement. Here are the requirement and comments from the enhancement spot. Once you start checking fields to not Re-ATP you need to account for all scenarios that might occur which requires extensive testing.

Do not Re-ATP on change of:
1. Ship-To ->  rv02p-weupd
2. Shipping Condition ->  vbak-vsbed
3. Re-Routing sy-ucomm -> = 'RTGR'
4. New route vbap-route -> yvbap-route

Additional Checks are required due to the way the user enter data into the screen. The user are changing multiple things at the same time, like the ship-to and quantity. Since quantity was changed the order needs should Re-ATP, so need to have checks up front to determine if the check for the items changes mentioned above should be checked.

Re-ATP on change of:
1. Item quantity (vbap-kwmeng)
2. Plant (vbap-werks)
3. Item Un-rejected (vbap-abgru becomes blank)
4. Requirement Type (vbap-bedae) Porcument Tab overview
5. Item category (vbap-pstyv) Front Screen
6. Item "Fixed date and qty" indicator (vbap-fixmg) Schedule line tab
7. Item piece count (vbap-umvkz)
8. Item UOM (vbap-vrkme)
9. Complete delivery indicator (vbak-autlf) Front screen check
10. Delivery Date (vbep-edatu)
11. Availability Check (sy-ucomm = 'PORE') Item
(sy-ucomm = 'BVFP') Header

This enhancement is in the Include FV45PFAP_VBAP_BEARBEITEN_ENDE Form FV45PFAP_VBAP_BEARBEITEN_ENDE. You will need the help of an ABAPer on implementing this type of change.

---------------Original Message---------------
From: Laurie Crow
Sent: Monday, August 15, 2011 2:56 PM
Subject: Re-checking Availability

My questions seems pretty basic but all of my reading is not providing an answer. When we make certain changes to our sales order (OR), SAP is automatically re-checking availability. Where can we control which data field changes trigger this activity and which data field changes will NOT trigger this activity -- re-checking of availability?