My apologies ... it was a type and I did mean the 727
Eastwest loco
Yep, I dealt with Ron Stone and Dudley Bellchambers (at DPO and BWT respectively) and without fail, nearly every Friday, we'd have a discussion around which way the round robin 997 998 evening Fokker flight for the following week would be routed ... service BWT first or DPO ?
With regard to the freighter, sometimes the 2211 DC9 would not return to the mainland as the scheduled 498 HBA LST MEL service, instead coming back as a dedicated 2212 HBA MEL
As for the four digit flight numbers, we assigend (generally) 1900 to 1940 for specials and predominantly, they were for groups on the east coast operations.
Eventually, we migrated to the three digit series (and two digit if necessary) where we could, primarily for "specials" or ad hoc inventory allocated to each of the city pairs. For example, we had a scheduled 414 416 and 418 MEL SYD operation ..... 412 at that time had never been used but eventually became a routine MEL 0600 SYD 0710 service.