Apple confirmed, that promo code downloads can't be rated, reviewed and they don't count as purchases anymore, so they don't will alter your ranking list.
Just wanted to let you know.
Anand here again from iTunes Store Customer Support. Thanks for writing back and letting me know your concern.
I understand that you are still not able to write a review. I know how disappointing it can be when things don\'t work out the way they should.
I am sorry to inform that it is no longer possible to rate or review an app if it was downloaded using a developer's promotional code.
However, I took the liberty of submitting your feedback to Apple on your behalf. Please know that Apple takes the feedback from our customers very seriously. This is the reason for our feedback page - to create a forum where our users can vent, praise or share whatever feelings they have to allow us to meet your needs, and grow as a company. I suggest that you use the link in order to share your feedback with us. I would also encourage you to share this link with all of your friends and family who wish to submit the feedback, and have them all submit the same request."
"It is no longer possible to rate or review an app if it was downloaded
using a developer's promotional code.
You can review this app by purchasing it on a different iTunes account
using something other than a developer's promotional code, such as a Gift
Card, Gift Certificate, or other payment options."