That discount was an offer Cloud9 made for some time, we haven't put it on the webpage, because very few users took advantage of it (less than 5% of ENBR customers) so, we thought there wasn't much interest in it.
However, is still valid: if you enter the below Coupon code:
CPN7915241649
in the Coupon field, it will activate a 70% discount on Bergen for FSX, if you purchased the FS9 version. Note that, the system will look at your email to check if you are already a customer for ENBR, so you have to use the same email you used back then.
Note that, EBNR is an exception: it's a Cloud9 product, and is the only Cloud9 product which is available in both FS9 and FSX version, and Cloud9 decided to offer a discount, rather than a free upgrade to FSX.
All our (FSDT) products, instead, are available in both versions, and the Serial Number is the same so, you can switch from FS9 to FSX without having to pay anything.