Albion,
Not sure what it is you find odd, but what you described falls in line with what exactly as LL described. If you are gone for 8 hours (assuming you have that much idle time available), you should get a relatively large draft because 8 hours is 48 drafts bundled (if you are collecting every 6 minute intervals).
If you are confused check out this thread, notably Fizzer's explanation
https://www.warzone.com/Forum/549257-increased-draft-sizeYou don't need to invest in statistics (I personally haven't and don't plan to, at least not anytime soon)