Council may require you to provide information on how you will be supplying power to the new lots as part of the requirement to approve the subdivison.
Ergon will not cross a side boundary now to connect power to your new lots so it will be up to them to decide where they will put the pole and how many will be required.
They will most likely get you to fill in a Network connection services information sheet an ask for an application fee of $250 they can take up to anywhere between 28 to 45 days to prepare your offer which will give you an idea of cost for connection. Catch the offer is only valid for 28 days so if you leave it a while before you proceed to connect the power you will be up for another application fee and the price may vary. This will only give you the price to get you access to your lots it will still be up to your electrician (or the new buyers) to connect the power from your house (new dwelling) into it.
My last application first came back at $3500 to move 1 pole for a subdivision, when I went to apply to actually connect the power (6 months later) the price offer had changed to $ 4500 so you will be at their mercy.
It is worth finding out, I have heard some horror stories of it being 3 - 4 times the amount of money of what people had allowed for.
Cheers,
Fourex.