The formula for Allocation effect on page 182 Book 6 looks incorrect. Its given as A_{i} = (w_{p} - w_{b}) B_{i}

where

w_{p} = weight of the sector/security on the portfolio

w_{b} = weight of the sector/security on the benchmark

B_{i} = return of the sector/security on the benchmark

I think this formula should be (w_{p} - w_{b}) (B_{i} - B)

where B = return of the benchmark

In fact, on page 182 they use the first formula while on page 197 (same chapter) the allocation effect has been computed using the 2^{nd} formula mentioned above.