Credit statement as a ledger

One period of your balance: openingBalanceUsd, then paymentsUsd (top-ups), adjustmentsUsd (refunds and corrections, signed), hostingUsd and aiUsd (what was spent, positive), and closingBalanceUsd. Opening + payments + adjustments − hosting − AI = closing, exactly.

from and to are ISO timestamps, to exclusive; with no from the opening balance is zero and the period is your whole history.