VOIPO bills to the 10th of a penny. I have a yearly reseller package with them and this is what I see each month.

Once the 1000 minutes are used I stat getting charged for each call at the cost of the call. If it is US or Canada it is .001 cents plus the 9% usage fee tax. If it is toll free calls there is no charge.

As a reseller the accounts you create can use their sip credentials to register an unlimited number of devices (there prob is a limit but they say unlimited) my PBX has 15 trunks on it all my company number this allows for multiple inbound and outbound calls.

All the accounts you create have their own sip credentials. It is up to you if you want to support this way of doing business as VOIPO will not provide support for your clients who try to use their sip credentials in devices that they are not making money selling.

For example one of my selling points is I will support SIP devices that I have certified as compliant. To certify I have the vendor or client send me a device and I will test with it and write up directions for it. I also support Asterisk as I have been using it for years. though if I have a issue with a client and they are not happy I cant run to support. I make sure I have another sure fire way to test if it is a voipo issue or mine, ie a softphone and the clients credentials. 9 out of 10 times it is a user issue.