I do it the same way as you do too. But maybe not less by 0.5 scoops maybe about 0.25. Observe your baby to see if he is always hungry after starting on this diluted version as it is also not right to dilute too much since they get a lot of nutrients from the milk too. If the milk is too heaty maybe you should change brand??
Im using dumex which is 1 scoop to 1 oz water. If i wanna dilute a little lets say im making 5oz bottle, i just put 4 scoops to 5 oz water (1 scoop lesser). Hope this helps.
You can also do 2 scoops and 180ml. I do it for my boy. Cause sometimes he drinks till nosebleed. Too heaty. Plus minus its okay
Mine is 1 scoop 30ml water...so if I intend to feed 90, I will put 3 scoops with 100ml water