Withholding Tax - condition type J1W1 value is blank

Dear SAP Gurus,

I'm using condition type "J1W1 Withholding Tax" in sales order and set up in VK11 with 4.5%.

But in sales order, the condition type is active but the value is blank. In the analysis, it shows 4.5%.

Any idea why?

Thanks,

Soo