Hi @Chris_Doty, happy to clarify!
The endpoints that we recently added to the Business plan include:
GET /user_invites
POST /user_invites
GET /user_invites/{userInvitedId}
DELETE /user_invites/{userInvitedId}
POST /user_invites/{userInviteId}/user_attributes
DELETE /user_invites/{userInviteId}/user_attributes/{attributeName}
POST /users/{userId}/user_attributes
DELETE /users/{userId}/user_attributes/{attributeName}
GET /user_attributes
I added those links to the post you mentioned to provide more clarity. Thank you for bringing this to my attention!