not exactly Halloween, but there will be a capture event this month. Probably Thursday next week, since it would have been announced already I think if it was this week.
I would guess some of them entered right at 12 then and it would count them with the next days total, so it's saying you entered 103 for Tuesday's shows, but in reality 20 or so of them would have been entered exactly at midnight Sunday night
If you have no records of horses being scratched. Look at the amount of horses who were entered vs showed for the prior day. There should be more shown than entered for 10/6. Another way to check is to tally the number of entries for both 10/6 and 10/7 and check to see if that number matches the amount of horses shown for the same two nights. Both numbers should equal the same amount