Hi @puffin , what can happen is an update to the gas charges due to calculations on the calorific value. 
I’ve been suggesting that they signpost changes better here

Just to point out that when viewing the details of an earlier bill, a click on the Download bill link will generate a new PDF with the latest data and today’s date at the top. 

If an adjustment was made to the balance at some earlier date, all subsequent statements will have to be updated to reflect the balance change. If a change is made, you should be informed about it, unless it’s really trivial. Here’s an email I received recently:
  

How much of a change is involved in your case?

Thank yu for your suggestion BPLightlog.

The readings and calculations are correct and remain unchanged.

I have just gone through an accumulation statement covering  the last few months that I received this morning. Here the closing balances for each month do agree with the next month’s opening balance. I note that each bill was regenerated today!

The problems are with the running bills, where the opening balance never agrees with  the previous month’s closing balance. I imagine that OVO are keeping a correct running value, so have rather been ignoring it. I do not understand why the values are changed by a regeneration of the bill, surely carried forward balances should be fixed?

They should .. have you checked previous bills to see if there’s any adjustment there? If not, I don’t understand how these changes are being validated 

The values are trivial, but vary each month. I do have a smets2 meter installed, but it is unable to communicate probably for geographic reasons, it therefore works as a dumb meter! I can understand why they should be recalculating bills for a running figure, but surely the brought forward balance should always agree with the previous carry forward balance. I will try to monitor the figures by taking more regular downloads

One other thing to check is if they are using estimated readings. Even if you supply readings, it is possible that they recalculate these to extend to a days end or similar. These are examples of this elsewhere. 
What is recommended from what has been seen, is that you provide readings on the morning after your billing period ends. Sounds odd but because smart meters send their readings just after midnight, any reading sent on the day appears to be changed, estimated to days end

I agree BTLightlog. I am wondering what an accountant would think! This is a figure that should be fixed on the database once calculated, or at least once made available for download! Yes I have been through the past 6 months as reported above! I may not spend so much time looking at all six months - maybe just the current one!

I will say that I do download the bill quite soon after sending in my reading as I get annoyed that, despite my giving them an accurate reading (i.e. I ignore digits after the decimal point), they then adjust the figure the next day!

Sorry you are too quick for me. I will try sending the reading in the next day. But I would still say that that is no reason to change the balance figures once they have been published!

Thanks Firedog

That certainly seems to be what is happening - but why are they going back into previous months, surely once billed the matter should be closed and a fresh start made. I put in additional readings on Sept 30 and these caused the values in the Aug-Sept bill to be changed yet again. This time I did notice that the start and end readings had been amended. I have not as yet gone through to see if earlier months have been affected.

The values are trivial but I am wondering whether to put up with this! To be honest, I wonder if I trust a company that keeps changing the figures in the bills after they have  been “completed”.  Surely brought forward and carried forward figures should be frozen. I am wondering if that would pass an audit as it does make balancing bills difficult!

I've been experiencing this ever since my account was switched from SSE to OVO.

The legal position is quite clear on this – a bill is a formal communication about the state of your account and, once issued, the supplier (OVO) must notify you of any and all changes to previous bills. They don't.

The supplier must also give you access to both the original and any subsequent amended versions of those bills. They don't .. on the contrary, they effectively gaslight you by deleting the old bills and only giving you access to the amended bills (which they typically haven’t told you that they’ve amended). 

The simple truth of it is that OVO aren't meeting their legal obligations. 

The irony of  is that the OVO system clearly has the ability to display multiple bills for any given billing period, because their system displays multiple versions of my old SSE bills which were migrated across to OVO..

The dates on OVO’s bills are also non-compliant, in terms of both consumer law and HMRC regulations,, because they show you the date you download them, not the issue and/or tax point date. 

As far as the law is concerned, there is no such thing as a “trivial” amendment to a bill .. any and all changes are material and you MUST be notified about them in writing. Failing to inform you effectively makes that amended bill unenforceable from a collections point of view. 

I have bills that have been revised at least six times without OVO ever informing me about any of them.

After getting nowhere with OVO I have reported it to Ofgem and I am in active dialogue with both Ofgem and HMRC and have proof of 27 amended bills that I have not been notified of in the less than one year since my OVO account was created. 

 now habitually check and document all amounts and changes on a weekly basis.

Hey @MCH59,

Sorry for the issues you’re having, 

When customers are re-billed, and statements are re-issued. There will be a note on the account about this, I'd advise getting the support team to raise this to our back end billing team. They’ll be able to advise of the re-bill and the reasoning behind it. 

@MCH59

I was also plagued with this on a monthly basis after being switched from SSE. In my case it was connected with the (equally annoying) issue of having actual opening and closing readings regularly displaced by estimates.

For me, both problems entirely disappeared once I began submitting readings on the morning after the end date on my monthly bill - i.e. on the first day of the new billing period, not the last day of the old billing period (as recommended above by @BPLightlog). 

Have you tried this as a practical fix?

Thanks

I am glad and horrified that I am not alone in this problem! The end of my billing period is nigh and I will hold back until the next day  to send in the readings. I also intend to talk to Customer Support but think that they will need a good story to persuade me that things are correct. I do at least hope that they are freezing the values at a change of tariff! I am also wondering whether this happens to people who have smart meters that work!

For some reason I am reminded of the guy who had programmed into an accounting system that the rounding values be paid into his account! I believe he was doing very nicely until he was found out!

Do other energy companies do the same thing?

Hey @puffin,

If you have a suggestion you could post this as a feature idea? That was other community members can vote on it and we can gauge the interest