The company released results for the first quarter of fiscal 2018, showing that costs for installing fibre-to-the-premises for established homes has fallen by just $7 since the end of June.
In the case of new homes, the cost fell by $79, while the cost of fibre-to-the-node connections rose by $41 since the end of June.
Installing HFC also rose by an average of $9 while fixed wireless costs per installation fell by $20.
Earlier this year, it was revealed that the NBN Co spent nearly half a million dollars on coffee for its staff.
There is still no change in the take-up of faster services. Among the fixed line connections, only 13% opted for the fastest 100Mbps/40 plans while 52% went for 25Mbps/5 plans.
And 30% went even lower, opting for 12Mbps/1 plans.
The fixed wireless and satellite customers do not have an 100Mbps/40 option. The fastest option for wireless is 50Mbps/20 and only 7% opted for that. The majority, 76%, went for 25Mbps/5 connections.
Satellite users were divided between the 12Mbps/1 (34%) and 25Mbps/5 (66%).