A seller who makes payments or furnishes services that come under the Act should do so according to a plan. If there are many competing customers to be considered or if the plan is complex, the seller would be well advised to put the plan in writing. What the plan should include is described in more detail in the remainder of these Guides. Briefly, the plan should make payments or services functionally available to all competing customers on proportionally equal terms. (See § 240.9 of this part.) Alternative terms and conditions should be made available to customers who cannot, in a practical sense, take advantage of any of the plan's offerings. The seller should inform competing customers of the plans available to them, in time for them to decide whether to participate. (See § 240.10 of this part.)