Works also for BKPF fields, I did exactly that with CPUDT, which was used all over the place in select statements for critical interfaces, and this way the join select on BKPF could be omitted, which also saved some time. Long live CORRESPONDING 
(and if the appended non-ZZ-field is appended by the standard one future day, you'll have a collision in SPDD that you can resolve within minutes).
Thomas