My KDP main dash end of day reporting matches my actual midnight (Pacific Coast), but the MTD tab rolls into the next day around 5:00 pm PT (0 hour, GMT).
In my KDP dash, sales die after 6:00 pm PT, though some days one or two pop up around 9:00 pm PT. KENP dies after 9:00 pm PT, though a little comes in just before midnight. Basically, after 9:00 pm PT, there's little to no activity until after midnight.
However, if I'm running ads, spend climbs to a four or five dollars an hour pace between 5:30 - 9:00 pm PT. When I stop an AMS ad, it takes about 90 minutes for clicks to stop piling up--so, two-hour delay in AMS reporting? Probably not consistently, though that's the way it's tested out for me at various times of day.
What's most troubling is those high-volume AMS click periods match up with a dead KDP dash (9-12). Now I pause all ads at 5:00 pm PT (counter-intuitively) and my net has gone up considerably.
But none of it makes sense.