It's hard to say. In the wild, they will forage throughout the day. On feeding days, I feed my animals twice a day.
For example - I go to work at 5 in the morning and get home around 6 PM.. I check on all the herps before I leave and when I get home. I feed my varanids at both check ins.
I am not a fan of letting a monitor eat its fill. If your monitor eats 22 crickets a day at one sitting and then stops, I would offer 10 in the morning and 10 in the evening.