If we limited the amount of units that were required to receive the admin-issued bonus, we could engineer actual competition between trade factions. We might actually see Universal-hired mercenaries posing as Xenos, for instance.
Limiting the time in which the deliveries must be made might work too. If for instance, the QCRF get a prize of so many million to receive so many ship hull panels at Southampton, they will either fly as Bowex or BMM for the Queen, or they will pay traders to bring in the materiel, sending out escorts to guard the incoming panel deliveries which are needed to arrive on time.