This isn't technically correct. If you're already eating at a deficit you should consider eating some back to ensure that your net calories don't go to low.
I probably wouldn't eat the full 500 as unless you're wearing a heart monitor it's probably inaccurate, but if you're eating at a deficit already then I'd probably eat maybe 200 extra - but then again that would just cover my after gym snack! So it's not like I can gorge on something yummy!