Did the cover exchange get more expensive?
Was that announced or is it a bug?
Wow, I logged out and back in, and it went back to normal.
But, when I try to exchange a cover 5★ for the Sam Wilson one, the price goes back to 1000, same thing happens with 4★s after that.
You should try to exchange a 3 star first and see if you get the lower rate on a 4
If I exchange the 4★ cover first, the cost stays normal. If I exchange a 5★ for any other, the cost stays normal as well. The bug that sets all the costs to 1000 only happens if I try to exchange a 5★ cover just for Sam.
Latest swap is supposed to cost 1000HP, compared to 650HP for other 5s. But it definitely is not supposed to make all swaps cost 1000… 
If you try to swap for a latest 5, the cost is 1000. This is basically an over ride to the normal 5* swap cost of 650. When you next try to make any swap the system remembers that over ride cost of 1000 and continues to display it even though it can never be relevant for a 3* or 4*. As soon as you select an actual cover that you want to swap for Peggy, when you get back to the cover exchange screen it will display the actual cost, and you would never be spending 1000.