Profitability is the same at most pools.
While we are 'expected' to find multiple blocks per diff change, i.e. multiple blocks per 2 weeks, profitability wont be affected much by changing pools.
You can't predict luck and luck is the biggest factor in PPLNS.
Of course if the pool gets 'too' small then that will noticeable affect Profitability, a fact that certain smaller pools like to hide from their miners, however we've been growing pretty well over the last month ... so that's not currently a concern.
It already got too small as soon as you dropped to less than 20 blocks per month expected. That's pretty much the minimum amount of chances to avoid what is going on right here. You can't ignore time frames when you get small and try to relate a diff% in your current state with when you had a much higher expected block %
This place has turned into a social experiment more than a mining operation
So ... can you back up that comment with maths?