Income Graph Not updated when invoices manually marked as Paid

[Outpower Hosting]

If I were to go into an invoice and go into the 'Options' tab and set the status to 'Paid' and save the invoice, that invoice amount does not update/reflect in the income graph. I am not sure if this is how it's intended to work.

The income graph gets updated only when I use the "Mark Paid' option in the invoices list. There are cases where I do not want to use the 'Mark Paid' option since it automatically sends an email to the customer. What should I be doing to have an invoice income reflect in the income graph but at the same time NOT have the email go out to the customer?