Pay Item out of balance error

dear All ,

while doing voucher match , if i change the tax amount it is giving an error 'pay item out of balance'

by default tax rate is 5% , invoice amount is 1139 , tax on that is 56.95 , but on supplier invoice it is 57.95 .

so I am changing tax amount manually while doing voucher match , i am adding 1 dhs diff in the last line of voucher match .

taxable amount + tax amount is matching with the total gross amount .

error description is as below :

A form level error has occurred. CAUSE: The gross amount should be equal to the sum of the taxable   and non-self assessed tax, or equal to the sum of taxable,