Do I really need a VAGCOM for a tune?

I am the happy owner of a previously owned Flashzilla. I was reading the directions on using it on my car and Malone's notes a VAGCOM may be needed to remove any trouble codes that may present during the flash process. (I'm guessing from maybe the car being "on" but not running but, honesty, I am not sure." That said, do I really need to purchase a VAGCOM? Do the codes clear after a time of running? From what I can tell, they run about $300 and, darn if this "little" mod isn't becoming more and more expensive.

Anyone have thoughts on this product?

http://ift.tt/2sCSBJn

Any input is appreciated.

Drive safe.

Do I really need a VAGCOM for a tune?