Running balance in your credit history

Every row of your credit history now states the balance you were left with after that charge or top-up, so you can reconcile the ledger against your wallet without adding the column up yourself. The figure is derived backwards from your live balance, and it is deliberately left blank wherever it cannot be supported — on rows from before credits replaced the old per-product meters, and on the legacy rows that count decks rather than credits. A blank there means "no balance to state", never zero.