Consult vs. Serve
Americans do not make a clear distinction between serving and consulting. They go hand-in-hand. They are two sides of the same coin. Consulting is a service to the customer.
Serving should include bringing into play ones subject matter expertise. However, an American consultant, supplier, vendor, seldom sees themselves at eye-level with the customer. The customer is always in charge.
Collaboration in the American business context is defined first und foremostly by the customer. They not only define what they want, but also to a significant extent how they want it.
The American customer expects the supplier to deliver a product or service as defined by the customer. The customer expects the supplier to orient himself fully towards their individual needs and to respond as quickly as possible. And the supplier is expected to adapt to any change in scope.