(17)This Regulation should set out the agreed allowances to be applied to the anhydrous mass of each fibre during the determination by analysis of the fibre content of textile products, and should give two different agreed allowances for calculating the composition of carded or combed fibres containing wool and/or animal hair. Since it cannot always be established whether a product is carded or combed, and consequently inconsistent results can arise from the application of the tolerances during checks on the conformity of textile products carried out in the Union, the laboratories carrying out those checks should be authorised to apply a single agreed allowance in doubtful cases.