Event R721 Restrict Contracts during creation of disconnection / reconnection order

In one of our implementation, we create disconnect order in background by calling FM 'ISU_S_DISCDOC_CHANGE', and we have troubles in deciding which devices to be disconnected and some devices are not even exist in the itab XY_DVALOBJ (BAPI Definition ISU_SERVORD_EDCN, Method SET_ORDERCODE_DISCONNECT) for you to choose.

SAP use a unique way to find out Contracts that can be disconnected. Basically SAP will check contracts that are listed in the open overdue items against dunning activities (FKKMAKT), and then check against Dunning History (FKKMAZE), if records exist, the contract can be disconnected. Thus, sometimes when you reverse the dunning and then re-run it again, some other devices are available for you to choose again, it's kind of magic. Lol~

Anyway, this can be resolved by enhancing event R721, you can either refresh itab T_DISC_EVER, so that all contracts are taken into consideration, or, define your own logic to include more contracts to T_DISC_EVER.

Technical Information:
Program: SAPLES34
Include Program: LES34F46
Form: DCORD_DARK_PBO
Then,
FM 'ISU_DISCDOC_ENVIRONMENT_SELECT'
Then,
FM 'ISU_GET_EVER_DISC_RELEVANT'
Then,
FM 'ISU_DB_GET_POS_DISC_RELEVANT'