This is the pricing model we have decided works best, and considering we also have to deal with people who obtain nulled versions of our themes, it would make it too easy for them to simply pay less to end up with what our legitimate customers pay full price for. You can get an idea of update frequency from the
version history here.
In order for us to allow such a significant discount on a theme purchase, the customer needs to have used the affiliate links on our website so that the referral is actually awarded to us by the hosting provider. If for example, the customer has been browsing other websites and then decided to sign up without clearing their browser cache, then the affiliate referral will potentially get awarded to another site, thus AppThemes does not show as the referrer from the hosting providers records. This is why we ask you to do this to prevent it happening, and as long as you follow the promo conditions you really have nothing to worry about. We have nothing to gain by making a potential customer angry before they've even started using one of our products.
It's ultimately your decision as to whether or not you want to go through this process, but hopefully my explanation helps. Thanks :)