Changing RMA disposition costs with BPM

We have a site that wants to set costs to $0 when dispositioning RMA’s. I have set up a post-processing BPM on GetNewRMADisp that will automatically invoke the method to check “Override Cost”, but I’m having trouble filling those 5 cost fields with 0’s. I tried to use 5 Set Field blocks, but that doesn’t seem to be working.

Can you send an image of how you’ve started?