Loaded versus stripped can also matter. If you view points as being worth $16-$17 each use (that's what you can rent them for), knowing you will pay the maintenance fees of $7 per point, each extra year worth of points can be viewed as being worth $9-10. So a fulled loaded contract with banked points may be worth $20 more than a stripped contract.
On a separate note, some agencies are consistently 5% to 10% lower than others on some contracts. A couple of agencies tend to have more distressed sellers, who are wanting to sell in hours, not days or weeks and they charge a lower commission, so they tend to have lower prices. These agencies could have "worse" customer service and response time, but they don't represent a scam risk, just a patience and frustration risk.