How are sales attributed to MageMail?
A sale is attributed to MageMail if a customer clicks through on an email up to 30 days prior to an order, or if they open the email without clicking through up to 7 days prior, or if they use a MageMail-specific coupon code.
Google Analytics tracking comes standard, so you should be able to cross reference order attribution in Google Analytics as well, if you have eCommerce tracking setup in there.
By default, orders are attributed so long as they are not cancelled, held, or closed. Attribution can also be limited to certain order states.
The revenue amount is based off of the grand total, and here's why.