As you know, the cost of maintenance service contracts is primarily a function of contractor labor rates, costs of parts, travel distance, shipping expenses, etc. and the ability of the parties to negotiate a good deal. If you have squeezed everything possible from this equation, you may want to consider your operations.
I'll get to the point. $6.50 to $7.00 is a fairly low average for an express exterior, in my opinion. Obviously, if you could reach a higher average, your bottom line would improve and contracted PM, etc. under the existing conditions and terms would be far more affordable.
Instead of rooting around looking for an alternative to the service providor with whom you may be very comfortable with, perhaps a better approach would be to consider getting help to boost sales volume and/or average revenue that would provide you with a more robust benefit.