Worsening performance in Turtle

I told you months ago about the sense I had that while I learned the tricks to play the most structured layouts in Mahjonng Titans e.g. Fortress, I seemed to lose the ability to win at Turtle as naturally as before.  Let me show you in numbers (the few numbers I have):

I think the scores are for about 18 months of play, from my first game in late 2010 to the last in January or February.
As you might expect, my best result is in 2012, with another two top-fives just the month before.  Basically my recent games won are good compared with my old games won.  This implies improvement.

Comment on using proxy measures: 
Of course the real data I would have liked to use is my wins and losses over time, to see if I won more (percentage wise) more recently than in the past.
I couldn't find such records in my game, but I found top-five "High Scores" with dates, which I am using as an alternative measure of performance trend over time.  Make sense? 

Now check out my scores for the other layouts:

Fortress seems to show a similar trend: top score in 2012, another two top-fives in Oct/Nov 2011.
Spider shows all five top scores come in Oct 2011 or later.  That is, better than what I played earlier --> improvement too.
Crab is somewhat similar; three top-fives since Oct 2011, just like Fortress.
Cat has four of the top scores in Sept-Oct 2011, and notably the number 2 top score from all the way in 2010.  Not as clear a picture of improvement with the Cat configuration.

Now look at the Turtle scores: of 28 games won in 16 months from say Oct 2010 to Jan 2012, two of the top five are in the early days: December 2010 and January 2011.  The remaining are in late 2011.  Compared to the other configurations, my top Turtle scores are not clustered in the most recent past. 

Or you could look at this picture I made by plotting the top 5 dates for each configuration in MS Excel:

Strongly improving: Fortress and Dragon
From rank 5 (or imagine the lowest rank wins in the blank space to the left of the chart) up to the top rank, the Purple Fortress appears to be marching up (improving).  To look at the best three scores in fortress and dragon, the message seems to be "the best is yet to come."  

Possibly stagnant: Spider and Cat
The performance in Spider is mildly falling, with best performances around October 2011 not looking likely to improve.  Cat is the same, if you ignore that the #2 performance in 2010.  Not getting better.

Weak outlook: Crab and Turtle
The green crab is almost certainly falling down, better past than future.  And the turtle?  It's a bit haphazard, but it's also sweeping down. 

It's not just my imagination, I used to play better Turtle before I learned all those specific tricks.