There are three ways to handle DID's on the SX-200:
1) Make the extensions of EVERYTHING match the last X digits of the DID DNIS digits (use number of digits and absorb as necessary) - This is good if you can match up everything or have very old software (think floppy disc based)
2) Use Abbreviated Dial form... In form 15, set the N to the number of digits, then set Absorb or bring the length down to to 3 or 4, then use Insert to add the Abbreviated Dial access code. Now in the Abbreviated dial form, you add the 3-4 digits of the DID as the Index number, and set the destination as the extension. - This was the most common way to do DID's in the SX200 up through about ICP release 3 or 4.
5) Use System DID Routing Table - Very similar to #2, except in the DID routing table you put the entire digits received from the carrier, this became available in ICP release 4 or 5.
You must pick ONE way to do it, you cannot do some like #1 and some #2, they must all be the same.