Services set up as “hours or miles, whichever comes first” can now be part of a preventive maintenance trigger chain. Your 400-hour / 10,000-mile service can trigger your 2,400-hour / 60,000-mile service, and the bigger service comes due on the right cycle.

Open a PM plan, go to Service Schedule, set Combine Mode to Trigger and turn on Allow “Whichever Comes First” Services in Trigger Chains. Then pick the trigger in Triggered By on any service.
