My understanding of it is from breastfeeding, so hopefully this is of some use. I have no idea how much he took, but like you say we brought the feeds closer together as bedtime got closer.
So on 3hr EASY we were aiming for 7am, 10am, 1pm feeds. I then did a 3pm, 5pm and 7pm (and 9pm until approx 12 weeks). It is just to give them the opportunity to get as many calories in during the day as they choose - and often helps with the fussiness too!