Good question. The truth is that it's a combination of a number of factors. If you look at my 30s graph you'll notice that it's made up of 3 sections. The first is very up and down hovering around breakeven, this is when I first moved up to the 30s and had to adapt the gameplan that I had been using up until that point due to facing 'thinking players' for the first time (I speak about this in the video-pack). This is also when I first started working with husng.com coach HokieGreg and thus was adjusting and readjusting certain problem areas (aka leaks) to make my game more well-rounded.
You can see when things started falling into place in the 2nd part of the graph which is a super steep incline with very little fluctuattion.
And the final part of the graph, a shorter but equally steep slope in the wrong direction, is made up of a number of attempts at 4 tabling (I generally play 2 or 3) that clearly didn't pan out well. You can see by my stats that I've never been a huge volume player and one reason for that is that I've never really enjoyed being a big multi-tabler (which is why I stopped playing 180s eventho I was very profitable at 30-35 tabling with 33% roi over nearly 4500 games). I also never used sharkystrator for the 30s and therefore faced some increased variance, as will happen when only sitting second.
And speaking of variance, I'm pretty sure I ran quite a bit below ev at the 30s (not to mention 50 buyins below ev at the 100s), but I can't remember 100% on that first part so don't quote me on that just yet. I actually requested all my old hhs from PS yesterday so I can post a full ev graph, but they said it might take a few days since they're having some issues with it right now. But I will for sure post it once I've received and imported them all so keep an eye out for that if you're interested. 
I hope that answers your question and please let me know if you have any more.
Cheers,
S.

Hi TC,
 
When employing a game-plan as aggressive as ours, it is an absolute certainty that there will be times when things don't work out as we had hoped. In fact, there will be MANY of them. The thing to remember, however, is that as long as our lines are profitable long-term against villain's likely range and population tendencies in that spot, each individual case is relatively irrelevant.

Also, I mention in one of the classroom videos that when facing an opponent, specific reads will outweigh all other considerations, including our established default strategy. This means that when our 'read' is that our opponent is likely to call with a much wider range than the general population tendency that our game-plan is dependent on, we need to make the necessary adjustments.

However, in the pack I also stress that we should be very careful not to OVER-adjust based on one or two hands or even based on our own perception of how our opponent will react (since we really have no idea if our perception is accurate or not). As I mention in the videos time and time again, the idea is to be relentlessly aggressive - and this is the key part - until our opponent gives us a reason to stop. So although we, as thinking players, might assume our opponents will adjust their ranges based on seeing us take an aggressive action, the reality of the matter is that at the lower-stakes, this will often be a wildly incorrect assumption, and so we should force our opponent to prove it to us before we give them credit for it and make significant alterations to our predefined strategy.

Or, as Mark Twain once wrote, “It is sound judgment to put on a bold face and play your hand for a hundred times what it is worth; forty-nine times out of fifty nobody dares to call it, and you roll in the chips.”