GST calculation problem in Adobe Pro DC

I need to calculate 10% of a sub total price (for 10% GST), I'm working in a table, and I have calculated everything else above it to work with each other, now I just need 10% of that subtotal price to calculate itself. I have change the follow order of the fields in set field calculation order. I use Adobe Pro DC.

Used formula in Custom Calculation script:

var f = this.getField("subtotal ex GST");

event.value = f.value * 0.10;

Subtotal is working and total is working as well. Just not the GST part.

Thanks guys