Adding two wagetype value in a PCR

Guru!

we are using ECC 6.0

I am configuring payroll..

This is the scenario.

There is one wage type: home allowance for which we have given USD 300 to a particular employee.

If that employee takes 4 day leave (non paid) as per rules, this should reduce his home allowance to USD 260

Now we want to add this wage type calculated value i.e. 260 with another wage type: transportation allowance which is fixed as USD 70 (having no impact of leave) and put the value back in wage type transportation allowance.

Can you please help me out with the PCR.

Regards

SH