27 oz is absolutely FINE for an 8 month old. The recommended amount is 20 - 24.
By splitting her feeds into a few ounces here and a few ounces there, you risk her taking even less as time goes on. She starts to learn that there's no reason to fill up NOW because there is more later. There's not really any harm in that, I don't think, as long as you don't mind making bottles that many times a day and offering small amounts. But, if you want her to take a few GOOD milk feeds of 7 - 8 ounces each, then at this age now that she is showing signs of taking less at her milk feeds, then it's a good idea to only offer it to her 3 times a day - morning, midday and bedtime.
The first day or two she may still take a smaller amount at the breakfast and midday feeds because she doesn't "know" what's happening yet, but in a couple of days she wills most likely start taking three good 7 - 8 ounce bottles. Even a 6 ounce is fine - a 6 in the morning, a 6 at lunch and 8 before bed is still 20 ounces! If you get 2 ounces in cereal in the daytime then you've got 22 which is even better!
By offering babies fewer feeds they really DO start taking more at each feed. The same thing happens at about one year, when they stop taking much in the morning and at lunch time, it's a sign to get rid of the lunch time bottle and just offer two per day....fewer feeds = more milk.
