Prices for delegations have dropped in cases where the steemprice relative to the payment coin has dropped. But if you purcahsed your delegation more than a couple of months ago, our base price for a delegation relative to the price of Steem has gone up, as demand was so high that we couldn't keep any inventory.

The renewal discount is relative to the current price for purchasing a delegation. Basically it is a 7 day discount to current pricing that we give because whenever we give a new delegation we lose 7 days before we can reassign that delegated SP: so it's more efficient for us to renew an existing delegation than it is to give someone a new one, so we pass on that discount.