The views are not based on the calendar day, they are based on the past 24 hours. It's a running total that get updated throughout the day. So, if you check your daily page views at 1pm, you are seeing your views from approximately the last 24 hours - 1pm the previous day to up to 1pm that day. If you check it again at 3pm, your daily view total might go down, because you happened to have had some traffic between 1-3pm the day before, but you didn't have as much during that time that day.
As for the hubscores, there really is just so much that goes into them that it is hard to say. I have started a new hub, put nothing more than a title & two key words, and left it sitting for a couple of days unpublished; it had gone up to a hubscore of 60 before with nothing written in it. I have others that I have added some content to, and then the score drops below 50 before publishing. I have some published that bounce between a score of 70 to 90 back and forth with no changes in content.
Hubscores are really mostly for your own benefit; it gives you an idea of how original and well written your article is. When people outside of hubpages do a search and find your hub, the hubscore means absolutely nothing to them. So really, as long as you are satisfied with the quality of your hub, it's nothing to worry about if it drops.