As an agent myself, I wouldn’t advice such. All our clients have done it themselves with us just double checking if the proper format were followed along with if questions were addressed. And we’ve not have any negative outcome so far. If one is able to gain an engineering degree, then he/she is capable of writing the CDR. You need to be mindful that it is expected that you’ve done the actual CDR yourself using your own words. If you hire a company to edit it for you, you’re already putting yourself in a compromising situation because you can’t claim you’ve done it yourself when EA is very particular about such thing.