As the purchaser of the WMP, you can choose whether you want to be listed on the plan. If you choose not to be listed, you won't be counted as a team member, but as the purchaser of the plan, will maintain your ability to edit and view the WMP.
If you want another member of your company to configure the plan, but don't want them to be listed on the team in the PDF printout of the WMP, you can choose not to add them. In the "Add Team Members" section (step 1, number 3), deselect the "List on Team" checkbox under their name and click on the update link next to it. If the plan configuror will not continue to be involved with plan changes, then just turn over configuration permissions to one of your customer's team members and then delete the configuror from the team list.