This requires a balance of data accuracy (tracking the asset) and schedule accuracy (updating the duration).

Option D is correct because it uses Field Service Mobile Flows , which is the best practice for guiding technicians through complex processes.

Data: Creating a Work Order Line Item (WOLI) is the correct data model to track work done on a specific (secondary) Asset under the main Work Order.

Schedule: The flow can update the current Service Appointment's Duration and Scheduled End to reflect the reality that the tech will be there longer.

Automation: Triggering a "Scheduling Recipe" (now typically handled via Flows/Optimization services) ensures that if the appointment runs long, subsequent appointments for the day are automatically shifted (Reshuffled) to prevent overlapping/late arrivals.

Options A and C fail to update the schedule duration, meaning the tech will likely be late to their next job without the dispatcher knowing. Option B creates a second appointment, which is administratively heavy for "just looking at" another asset during the same visit.