Entry-level is a bit misleading haha. It's not wrong since it means entry into hi-fi (as opposed to mid-fi and low-fi), but these are arguably endgame level phones.
The HE-400i is pretty new so I doubt they would lower the price any time soon. The Sennheisers have been around for ages so you'd probably get a better deal on second-hand or other sales. So overall I doubt this would be a very useful drop.