Dropping feeding?

My son will be 8 months on the 14th and we have been noticing he’s been wanting to play with his bottles more and more. He’s usually pretty serious about his morning bottle but the middle two he chews on the nipple and talks and takes forever to finish. He used to get upset when a bottle was over and he doesn’t seem to care much now. When do they usually start dropping a bottle? He’s a reflux baby who has extra calories added to his formula (24 calories vs the norm) and he drinks 6oz per feeding (currently 4 feedings) so a total of 24 oz. He also eats 2-3 meals a day (real food). His afternoon feeding he also spits up a lot (spitting up a lot was his norm but has gotten a bit better recently) We see the GI specialist on the 19th and will ask him then too but I’m curious what’s the norm for others!