At this time (always SCWN), the policy is that if you are not changing anything else but the fare (i.e. going from Q to H) in order to be eligible for a redemptive upgrade, we charge only the difference in fare - no service fee. Since the majority of passengers who wish to use miles book the ticket in the upgrade class to begin with, there aren't that many calls with this request so an agent may have to review the rules before processing the change.