Whenever a recipe states a measurement for a solid ingredient (i.e. 4 3/4 ounces flour), you will need to weigh it. An 8-ounce cup measures 8 ounces in volume (not weight). For example, if you fill an 8-ounce cup with feathers and an 8-ounce cup with rocks, they will both fill the cup to the top to create a volume of 8 ounces... but they will vary drastically in weight.
There are many threads in the forum on weight vs. volume.
Here is one post that provides a link to some common volume/weight conversions. Hope this helps. Cheers!