69.8lb is large, you would probably want her around 48lb considering her mum is 78lb (high end of average weight) and father is 77lb, quite small for a male, so her mum is a bit bigger than average and dad is a bit smaller than average and yet she is pretty big!
I would take her off puppy food and put her on the adult version. Does she has a nice trim waist, can you feel her ribs through a thin layer of fat? If you feel she is obese, I would reduce her food intake. It is best to grow them slowly and she is only 6mo, she has another 2 years or more of filling out left.
If if were me, and I have taken into consideration that she doesn't have a waist and is carrying too much fat then I would reduce her food intake down to 3 cups a day.