AFAIK this is not correct - at least not for an isdn landline
My system records outgoing calls as missed when one gets an engaged tone or disconnect while it is still ringing. The moment you hear any kind of announcement (i.e. voicemail, invalid number, not available, etc.) it records an outgoing call. I do not get charged for missed calls.
Also if one is on the closer option the call charge if you disconnect immediately on hearing the announcement is negligible as you are only charged for a 1 second call.