Why? The point of expiration is to provide BitAsset holders with a guarantee that they can exit into BTS within 30 days at or above the price feed (in BitAsset/BTS). That is still true. They will eventually be able to put a relative BitUSD sell order at 0% offset from the price feed and then just wait. We can guarantee that their order will be matched within 30 days. There is no need to force expired orders to buy 10% below the price feed, unless of course their collateral ratio drops below 200% in which case they should then be margin called and buy any BitUSD sells at a price that is above the price 10% below the price feed (BTW, this is probably a good time to bring this comment to the attention of the developers).
Right this makes sense. As long as they'll get margin called if the collateral goes too low then there's nothing wrong with letting their order sit at the price feed. At first I thought it was unfair they wouldn't have to pay interest, but at high bitasset demand interest rate goes to 0 anyway.
There are good reasons why the price feed was first introduced. We don't want the short market to drive the growth of BTS priced in the underlying asset of the BitAsset, that should be done by the market between actual BitUSD holders and BTS (or actual USD holders and BTS on outside exchanges). Removing the limitation could instead break the peg and drive the value of the BitAsset to zero. Now that particular problem doesn't necessary limit us from changing the short limit to slightly above (in BitAsset/BTS) the price feed, say even 10% above (since if it does not reflect outside reality the price feed won't follow the shorts). But the worry I have with that is that it prevents existing BitAsset holders from having the guarantee to exit into BTS within 30 days by simply offering to sell at the price feed. If the shorts are very eager to short sell the BitAsset, the actual BitAsset holders may be forced to sell their BitAsset at a 10% discount from the peg.
When I say above the price feed i mean that the bitasset is overvalued (so feed is in BTS per bitasset). I get super confused when the feed is described the other way so this is how I have to think of it

. If the feed is 100 BTS per bitUSD, then if there's a buy order at 115 BTS per bitUSD it should be possible to match that buy order and all other buy orders by shorting all the way down to the feed price for an instant expected profit (since you can expect bitasset price to tend towards the feed price). Then every time bitasset demand increases enough to make buy orders go above the feed, there will be an incentive to short the bitasset since you can be certain you will profit from the amount that the buy orders exceed the feed price. It should never be possible to short below the feed price (so short orders at 90 BTS per bitUSD should not be possible if the feed is at 100 BTS per bitUSD).