Cheaper CVC = Higher AVC = Slower Speeds
First, I want to make a few points:
1. The costs of NBNCo are fixed and do not rise substantially with more customers because the bulk of the cost is is building the network.
2. NBNCo has two sources of revenue: AVC (connection charges) and CVC (data or usage charges)
3. NBNCo revenue target is costs + 7% (return on investment, ROI)
This means that if you reduce the cost of CVC this means that AVC will need to rise. There is little room to increase the price of the popular base plan (12/1Mbps) because of competition with mobile phone operators. Therefore it is the higher speed plans which will need to increase in price to cover this decision. The increase in the more expensive faster plans will make them less attractive.
Less people connecting at faster speeds will justify the Liberal government's position that most people are not prepared to pay for fast Internet (>100Mbps). Less people connecting at faster speeds will also mean less people downloading data because they have to wait for data.