Greg, we had a similar question around the discrepancy with the "Last Cast" numbers - both the stream total and for each email/content send. While your question isn't specifically referring to the "last cast" numbers, maybe this will help you make sense of what you're seeing.
Tallying up the Last Cast is not the way to account the total number of leads in a stream. If for example, you see 50k in the stream "last cast", this doesn't refer to 50k leads - it's 50k CONTENT SENDS, regardless if anything went out during the last cast. The total Last Cast tally is a summation of all of the "Last Cast" values in a stream. If some of that content wasn't sent out at all during a recent cast (e.g., no leads qualified), it will show the number of the last cast when something actually did go out - even if it was a month ago. And that will often inflate the "Last Cast" total number for the stream. You can't think of "Last Cast" as the number that was sent out last week (assuming you have a weekly cadence), but rather, the number that was sent our when there were leads that qualified for that specific content.
And finally, if you're using programs (instead of just emails) and have filters within the "email send" smart campaign to further refine your send, they will be represented in the last cast number - even if they never received anything. Which is why they don't automatically skip it and go on to the next cast they would qualify for that week (they would have to wait for the date of the next cast).
Clear as mud, huh?!
Thx, that is instructive..png)