I don't brew until my starter has come to a halt. I've had to push a brew day back a day or two in order to let the starter wind down. The reason I wait is so I can let all the yeast settle so I can pour off all the excess liquid. My starter is always a quarter pound of DME in 4 cups of water, boil for about 20 min, cool, pour into a half gallon growler, pitch yeast, and watch.
All that being said, I think you should be fine pitching your starter pack as is. I think that's what it's designed for. I use White Labs. I've pitched just a vial into 5 gal and been fine.