Ever since I had SM's installed, the indoor display has never provided
a sensible number for the Estimated Cost. It had always just shown the
total cost since it was first installed, adding the cost each month -
not taking into account the direct debits I was paying each month
against my account.

So, the indoor display was just left in a drawer, once the novelty wore
off. Last week I gave it another go and once it had synched its data,
it was showing some sensible numbers for this months cost/consumption.

What is more, the estimated cost of both E & G dropped to near zero
just after my DD went out. So it seems my SM's are getting some
feedback from my utility providers system.