We check your balance twice daily and at the end of the month we average those values to give us an overall asset under key (AuK) figure for your account. Transactions are cumulative for the monthly period.
If you are on a Genesis Tier 1 paying £50/mo in advance,
Sent Volume /mo
Genesis Tier 1
Genesis Tier 2
However during the month your average balance was £95,000 - you will then be billed in arrears for the difference eg £125- £50 (paid already) = £75 excess.
If you are consistently being billed for additional excess fees, you may wish to speak to your account manager and transition to the next tier.