Ann: Trading Halt, page-207

1 both
2 they don’t care. The costs are based on a single price per mobile handset per month flat rate so no need.
3 for mobile users see above. It doesn’t matter because I can make 1 call per month or 5000 and it’s the same price to the company.
4 for mobile users not required. Call centres use a different software altogether. Very complex stuff from Avaya.

As you can see once you hit a certain level and deal with the telcos direct, those costs and savings disappear.