Hi, 

I am trying to calculate an Allowance item in the salary slip. The contract has a custom field called x_ctc_mo (contract.x_ctc_mo)

The rule requires the medical allowance, basic salary, food allowance, and other categories to be deducted from contract.x_ctc_mo 

I tried 

result = contract.x_ctc_mo - rules.BASIC - rules.MEDA .... and so on.

However, the result shows the value of contract.x_ctc_mo - rules.BASIC only for some reasons other categories are not calculated at all. 

What am doing wrong?