In the reading history, include the difference since last month in the list to save us using calculators.

@jabbamp OK, I leapt to a wrong conclusion again, sorry. You asked  “include the difference since last month in the list.” For those of us with smart meters, the meter readings page will normally show a reading for each day. For those with dual-rate meters, there are two a day. 

I now see that you don’t have a smart meter, and that you presumably submit a reading once a month. That’s why my comments about which period’s usage to display probably didn’t make much sense to you, sorry.

In your situation, it would of course be helpful to see the month’s usage (or the difference from the previous reading) on that page. However, before we rush off to recommend this to the site’s designers, we should remember that more than 55% of household meters in GB are now smart, so they may think twice before spending time and effort on a feature to help a rapidly-dwindling minority of users. 

As @Jeffus pointed out, you will get a variety of views on the forum 😊.

I understand. But it's just 1 derived column which in terms of development is a very small amount of SQL code. A developer could add it in much less than 10 minutes.