Confused how my energy supplier estimates forward my annual consumption

[vintage36]

My energy supplier’s monthly statements give an estimate of my annual use. This, of course changes month to month. In the 12 months prior to joining them gas consumed was 15000 kWh +/- say 200 in all.
Readings with the new supplier:

START​	END​	DAYS​	kWh	Supplier kWh forecast​
04-May​	29-May​	26​	568.7​	14370​
30-May​	01-Jul​	33​	252.8​	14634​
02-Jul​	01-Aug​	31​	190.6​	14910​
02-Aug​	31-Aug​	30​	190.1​	14761​
01-Sep​	30-Sep​	30​	254.7​	14607​
01-Oct​	31-Oct​	31​	1232.2​	14013​

I fail to see how they arrive at those figures. Does anyone have ideas?

 

[DRSteele]

Suppliers base their forecasts on
1) your usage pattern, including recent trends and seasonal trends for your abode
2) the usage patterns in your neighborhood
3) the usage patterns in your city and province, especially as they relate to weather forecasts, both medium-term and seasonal
4) proprietary algorithms.

So you'll never suss it out.

 

[vintage36]

Just for anyone's info and interest. Here is a paraphrase of a reply I received.

The annual estimates aren't set directly by the energy supplier. The supplier has to forward any customer reading to a data collector who aggregates the last three years worth of readings and averages this down to 1 year. 
 My informant does not know the actual formula, but is aware that the more recent readings have greater weighting.