The everyday problem
A percentage, fixed fee, or per-task price describes only part of an engagement. Different scopes and assumptions can make prices look comparable when they are not. The internal oversight and excluded activities also affect what the arrangement costs to operate.
A practical approach
Provide the same workload assumptions to each provider and ask them to identify deviations. Request clarity on minimums, onboarding, optional services, and changes in volume. Keep pricing questions tied to scope rather than treating the lowest visible rate as the complete answer.
Try this with your team
Build a comparison using one fictional month of work. Include the provider fee and the internal tasks that remain necessary under each proposal.