Hi,
As of BW release 7.3 the standard behavior for RETURNCODE <> 0 is "skip record". Please refer to SAP Note 1610259 - Controlling 'Returncode' behavior in update rules. You can influence the behavior using RSADMIN parameters.
SAP advises to initialize the RESULT return parameter as a work-around for the old "skip value".
Please review SAP Note 1052648 - Migrating transfer rules and update rules for BW7.x for the migration logic and its limitations. The migrated coding using the second global part and subroutines FORM ... ENDFORM is in my opinion not transparent and not easy to maintain (although it should be possible to maintain). I suggest to rewrite the coding in an 7.x compliant way, i.e. w/o the overhead of the migration.
SAP Note 1527023 - Technical enhancement Routine source code; direct migration describes that improvements can be expected soon. However, SAP Note 1533114 is only released internally at the moment.
Best regards,
Sander