Brauer characters and the Harris–Knörr correspondence in p-solvable groups

If b is a p-block of a normal subgroup N of a p-solvable group G and b* is its Brauer correspondent in NN(L), where L is a defect group of b, then Harris–Knörr correspondents over b and b* contain equal numbers of irreducible Brauer characters over height zero Brauer characters.