Terms like "construction commenced" used to mean holes in the ground, tradesmen at work and visible activity on some site.
For the NBN Co, "construction commenced" includes activities like having a think about the high level design for an NBN area.
It's a bit like you or me coming from an intitial meeting with the architect who's knocked up a a couple of dream-home design concepts - then marching straight down to the bank expecting it to hand over the mortgage funding because "construction has commenced".
Prudent lenders and providers of equity capital seldom take kindly to novel definitions like that. It's an easy way to lose money.
The two "shareholder ministers" who represent the taxpayer in the Rudd/Conroy "investment-grade" NBNCo must feel much the same way. Here's their letter that should be read with the grossly misleading NBNCo's Annual Report.