Hello, can you please explain to me how "subsequent sell order" works?

I would expect that after entering "1%" and hitting "Apply" that the Sell form to the right would be calculated based on 1% profit, but instead the % field jumps to 4.449%. Is this a bug or am I misunderstanding this feature? I made a video of it.

http://www.youtube.com/watch?v=_2eCeIRz8is&feature=youtu.be