I'd say no, he's not having enough then. The general recs are that babies need at least 20oz of formula/ breast milk up until they are 1, most babies are taking 24oz+ at this age.
Most formula fed babies drop to 3 bottles around 9/10 months, the most common feeding pattern is a wake up bottle (usually a full feed around 8/9oz at this age), another feed early afternoon before their nap and a bedtime feed. In your routine I would do a bottle about 14.00, then the home made soup and some fruit around 16.00 then a bottle just before he goes to bed. That would give him 3 good bottles a day.
At 5am is he still sleeping when you feed him or does he wake, have the milk and go back to sleep?
Laura