Flaked wheat is not malted, therefore requires extra effort to extract it's potential sugar content, which will be lower than malted wheat. Flaked wheat is traditional in Belgian witbier and lambics, it contains more starch and higher levels of protein than malted wheat. It adds more mouthfeel than malted wheat and has a different taste, which is noticeable when used in larger quantities. If the grain bill consists of more than 25% flaked wheat you should consider a cereal mash, or precooking the wheat in order to gelatinize it so you can extract more sugars out of it. The addion of 6-row can aid conversion since the barley contains a higher percentage of enzymes than 2-row.