There might be a little confusion here. It also seemed to me like the tax benefit wasn't accruing to my total when I filled in the form, but when I read the FAQ it looks like a credit only applies if you owe money for the year. i.e. you don't get a tax benefit if you were already getting a credit for the year, which makes it seem like the form is broken but actually it's working as intended? (I could be wrong, this is not tax advice)
