Hi,
I suspect it may be caused by the following statement:
If five messages in a row sent to a given address result in a soft bounce, then Marketing will treat that address as a hard-bouncing address and stop trying to send to it. (Ref: Email soft bounced)
If there are 2 contacts who have been soft bounced 5 times and they are treated as a hard-bouncing address, there are actually 14 (i.e. 16-2) hard bounced emails and 11 (i.e. 1+5+5) soft bounced emails.
Then the total sent number 441 = delivered 416 + 14 + 11.
A soft bounce may occur because the recipient's mailbox is full, the mail server is temporarily unavailable, or the email account has been closed.
You can check whether there are duplicate contact records in your exported excel.