Best answer by Marc
Here's a link to a very good existing thread about how energy spend is calculated.
No company - which includes Pure Planet of course - is legally allowed to see your energy spend until after you join. So to start with it is calculated using an industry standard provided by Ofgem - classed as low, medium or high. Which is why we at Pure Planet review it after the first month to make sure that the level is correct.
It may be that the industry 'sees' your home as 'low' but your first month's use was actually quite high.
Does that help explain it? It may also be of use to
And on your second point about submitting readings from an economy 7 meter. This thread may be helpful. You can do this via the app