A method is provided for use in a network that includes a plurality of user plane functions that perform processing of user plane traffic sessions from one or more mobile wireless user devices. The method includes periodically monitoring resource utilization of the plurality of user plane functions to estimate a resource utilization level of respective user plane functions. Based on the periodically monitoring, the method further includes storing for the respective user plane functions a resource utilization level indicator for each of the respective user plane functions according a resource utilization level of the respective user plane functions. User plane traffic sessions for a given tracking area are re-assigned (moved) among the plurality of user plane functions based on the resource utilization level indicators for the respective user plane functions to achieve a desired quality of experience for the user plane traffic sessions.