2861.This section contains guidance about the ways in which sums to be accounted for under a PSA can be calculated. It recognises that in practice the sums to be paid under a PSA will rarely be precisely equal to what would be the income tax liability of the employees in relation to the earnings covered by a PSA. It does this by permitting PAYE Regulations to recognise approximations as to who receives the earnings, how much those earnings would have been and how much the tax liability would have been on such earnings. It derives from section 206A(3) of ICTA.