Regarding the note - just because you have activated the exits by following the instructions in the note, it does not mean that the already created orders will be updated automatically with the new logic. 
It works for new orders after activation, but for old orders after a recheck and a new release.
Since your customer does not wish to use requested quantity as a basis for credit release, you have 2 other options, which I have mentioned in my previous post: 1) change released orders are still unchecked settings in OVA8 or 2) create and set a custom VOFM routine in OVA8 to bypass credit limit check in case the value is not increased. Option 2 is more secure, but will solve the problem only for minus in confirmed quantities.
There are very limited options to resolve the problem only with the settings in credit management: your customer does not like the idea to use the requested order quantity as a basis for credit check and release, he is not satisfied with the results when using the confirmed order quantity as a basis, but apart from requested and confirmed quantity I can see no other meaningful criteria fot the sysem to determine the basis for credit limit checks.
The best approach to fix the issue (at least this is how I see it): 1) resolve you problems with ATP and 2) review your cutover times for production order confirmation, order taking and credit release. There seem to be something wrong with the planning if you have a lot of backorders every day. Probably you could use a different strategy for the problematic materials. Check also at what time the production orders are confirmed (probably you use partial confirmations) - you need the goods receipt to be performed before the credit department starts to release the orders, ideally it should happen before order taking starts.