Tds on rate difference commission

Consider an example

there are three parties A, B & C

"A" sells to "B" goods at 10 rs asking B to sell goods to "C" at 8 rs. For which B will charge commission from "A" and also the credit note for the rate difference i.e. 10-8=2. Is TDS deductible on such commission (which may be 8% of 8 rs)?

Please support answer with relevant case law if any