The use of %service_del_postun macro and the DISABLE_RESTART_ON_UPDATE is documented on the systemd package guidelines [1], so I think it's fine to use them. I think also that %service_* macros are the intended ones to be used by packages providind services, as are the one that account for systemd presets. [1] https://en.opensuse.org/openSUSE:Systemd_packaging_guidelines