On-time percentages are easy to quote and hard to evidence. These are the questions that separate a real network from a broker.
Every carrier quotes a high on-time figure. Ask how it is measured, over what period, and whether failed deliveries are excluded from the denominator.
Ask who actually moves the freight. Subcontracting is normal; anonymous subcontracting is not. You should know which operators touch your goods.
Ask what happens at 4pm on a Friday when a vehicle breaks down — the answer tells you whether there is a control desk or an answerphone.
Finally, ask for proof of delivery data in a format your systems can read. If tracking cannot be exported, it cannot be audited.