POMisc_MiscAmt refuses to update from an updatable dashboard

As the title suggests. I have a new dashboard where we want to be able to add/Edit misc charges to Purchase orders if they have been missed. It gives no errors at all and seems to update, but when I refresh its not doing anything and I cannot figure out why. Any pointers?

FYI, field help is saying the EpiBinding is “POHeadMisc.ScrDocMiscAmt” but I cannot find the associated table.