Hi Tharu,
You need not worry about "Service Maintenance Tab". If the service is registered through /IWFND/MAINT_SERVICE, then you can ignore this.
By maintaining suitable configuration entries, you can maintain/register service is Service Builder itself instead of /IWFND/MAINT_SERVICE. That is the goal of "Service Maintenance" folder.
If you want to configure "Service Maintenance" go here.
SPRO->SAP NetWeaver->Gateway Service Enablement -> Backend OData Channel ->Connection Settings to SAP NetWeaver Gateway->SAP NetWeaver Gateway Settings