VMS - before I start, I did not read everything you had to say; to paraphrase the king's adisor (and hence the king) in Amadeus, "too many notes" or in this case, words.
As for the billing of Voip, I think you may be missing a critical point here.
Question : Are you prepared to pay for QoS?
IP by its very nature is both sessionless, and agnostic of the data being sent, consequently the sequence in which packets are sent and received on the other side (and of course how many times the same packet must be sent to ensure successful transmission) is immaterial. In fact, it is, by its very design, meant to lose packets along the way, because they can be picked up later. Quality voice communication is not like this.
For non-voice, non sequence, non time sensitive, structured data (e.g. a file download - even porn) this is not a problem. However, if the third word spoken arrives before the second, .... then we have a problem, and YOU as the Voip user have a bad experience. (Any one ever experienced lag or jitter on a VoIP call??)
Are YOU prepared to pay a premium rate in order to ensure that your voice "data" packets arrive both timeously and in sequence???? If the answer is YES, then paying a premium rate to use your "MB" for this should not be an issue - as it should still work out cheaper than Telkom.
If the answer is NO, and you continue to use a non prioritised (new or hidden ??) protocol in order to route your voice packets, then you ought to be allowed to pay the normal data rate, but should not expect the premium service (which, frankly, you are experiencing a "version" of whilst the networks are not congested).
The other thing you must still consider is the interconnect costs, especially if you wish to terminate a call outside of the host network. From all you have written above and elsewhere, I cannot imagine that interconnect is a new concept to you, however it seems to have been avoided in the tirade above.
For the uninitiated, interconnect works like this : If a call originates on Network A ( be that voice data or otherwise) and wishes to terminate on network B (i.e. the network on which the called party resides - for example a British Telecom land line) then the calling party network must pay a fee, normally per minute, to allow that call to be connected on the other network.
The same principle applies to ISPs with traffic originating and terminating on different networks, however the fees have traditionally been waived, and or offset (nett billed) through a complex structure of agreements based on volume etc between the different networks. Another reason why this has not historically been billed is because ISPs have not had the infrastructure in order to accurately capture and bill these transactions - the number of hops between (as each interim carrier would need to be billed, and hence on-bill), and the possibility of each packet taking a different route makes this very very difficult. IP by its very nature is not circuit switched, and so each packet may theoretically follow a different route over different carriers and so incur different billing charges.
VoiP is different as there is a (mostly) known point of origination, and a definite known point of Termination where the call terminates on either a PSTN, or Mobile network, and so this can (and must otherwise the call will not terminate) be billed. Where the call terminates on another IP device (e.g. PC or smartphone) this becomes more difficult, especially so long as we live in the realm of dynamic IP addresses, but once this has been overcome and every possible IP device has been assigned a fixed, and so billable, IP address, and then I am afraid the days of "free" IP to IP calls is gone.
What makes VoIP billable (and therefor a premium service) is that in many instances the carrier preselects a route, and forces all packets over that route - both to enable QoS and to allow equitable and consistent billing. So, strictly speaking, commercial VoIP is a misnomer, as it bypasses one of the fundamental constructs of IP and forces the route over which the packets must travel, and disallows the ad hoc routing of packets which is a foundation of the TCP/IP network we have all grown to love and abuse.
If TMVC ( I think that is what you called them ) get to a point that they can determine, and so offer to prioritise and force route VoIP packets (with certain QoS standards in place) then surely it is their right to charge a premium for such a service. If your voice packets are so inconsequential that you are prepared to suffer an inconsistent, degradeable, and inherently unreliable service as normal IP, then I believe you ought to be able to "waste" you MB as you see fit at the billable rate you see fit, but then don't come crying when you (or another party) were incomprehensible for a large part of a conversation which required you to repeat yourself so many times that it would have been cheaper to use a landline.
Just my 275cents worth - how much my connection time cost me to write this
At the end of the day, I am jealous of you who have the choice and the opportunity to feel hard done by. I live in an area where I have Telkom ISDN, and that is about as good as it is going to get for quite some time. I am too far from Metro areas for any form of wireless broadband, and over 6km from tar, so what chance to I have for ADSL .... Enjoy your toys and be thankful for the opportunities afforded to you , some of us are not so lucky and WISH we could be "ripped off" at R10.00 per MB for international calls (which, I am lead to believe, equates to about 4 - 5 minutes which is not too bad I believe)
