For an exercise, try to put yourself in your customer's shoes when they do not get what they were promised at the sales meeting. The customer expects a service no matter what department of the vendor's organization gets involved in the product delivery. Your product has to live up to your customers' expectations within the boundaries of your product's advertised and sold capabilities. As for the once percent Raving Fans advice, customers will always appreciate your continuous improvements to your products and services as long as you keep delivering at the same level of perfection. Be prepared when you meet the customer.
Time is precious.
If you go into a meeting unprepared, you will waist everyone's time and lose the respect of the people you meet with. Place key emphasis on your account team. Able to provide immediate resolution of a service or support call. Able to provide accurate commitments. Able to provide accurate information.