Previous Pay and Tax figures from Previous P45

I have added previous Pay and Tax figures to a couple of employees from their P45s - their previous employers paid them a bonus after leaving - when I run their payslips for the current month the tax deduction figures are correct as they are both due to tax a tax refund as their bonus was taxed at the higher rate  - but it does not include  the P45 figures on their payslips for the current year - but it does show their reduced tax figures - which makes their figures look incorrect - can anyone help please