Yes. We need to ensure that £40 is authorised to cover the maximum cost of the reading. Some services such as queuing do not start the reading immediately and any credit on your Kooma account could be used up before the reading starts. Any unused credit on your account will be used towards the cost of your reading though. For example, if you have £10 credit on your account, we will still authorise the maximum call cost of £40 on your payment card, if your reading then costs £30 we’ll use the £10 credit on your account and charge the remaining £20 to your payment card (£10 credit + £20 on payment card = £30 reading cost).