2nd opinion about making up a infusions

Hi
Just want to check and get a 2nd opinion about making up a infusions. My wife and i take 3 times a day a mixture of herbs and i make them up in the morning. There are 3 different ones and we should be taken 3grammes each of each herb. So i make up 18 grammes for the first and other ones total of 54 grams in 800ml of steeping water. This we take 3 times a day, 100ml each person (because there is only 600ml left of the infusion), so my my question is are we getting the right dose this way? Eg according to our books, making up a single infusion would be one cup of 100ml per person with 9 grams of herbs, so doing a batch for day should be the same??

thanks