Trying to explain: The deemed payment of employer means what he is loosing from his pocket. He is loosing what he is paying to employee and HMRC. The figure given here, i.e. GBP 20938 includes both i.e employee salary and what is being paid to HMRC, how to separate two figures, because we need employee figure to calculate tax. so remember this formula 13.8/113.8 to split out tax and salary. hope this explains.