ServiceStack UpdateUserAuth RegistrationService

ServiceStack UpdateUserAuth RegistrationService

I'm implementing my own IAuthRepository, but I can't figure out how
UpdateUserAuth should be. the signature in IUserAuthRepository is:
UserAuth UpdateUserAuth(UserAuth existingUser, UserAuth newUser, string
password);
in ServiceStack code, it's used in RegistrationService in 2 different
manners:
UserAuthRepo.UpdateUserAuth(newUserAuth, existingUser, request.Password)
in UpdateUserAuth method
this.UserAuthRepo.UpdateUserAuth(existingUser, newUserAuth,
request.Password);
in Post method
Is it a mistake or the desired feature?