I was receiving WC when I applied for SSDI, so I still had income coming in too. I don't specifically remember having to document that, but I must have because I know SSDI knows about my WC because they lowered my backpay, my SSDI amount, and my kids' SSDI amounts to offset the difference (because with all of the above, I would be over the cap of 80% of pre disablity income on my SSDI amount.)