@MIW - Once again we are in the same boat. This is strangely similar to "Ohno", who regularly experienced the same traffic issues I had observed. My current issues started around the 21st of January after a very short seasonal high that always had started December 26 and (usually) lasts through mid April or May.
Then, this last Thursday or Friday my serps began to rise, a lot of upward movement and new positions, many at #1. I honestly do not like the #1 position, I prefer #2 or #3 since #1 get's isolated at the top, usually above the images where it looks like an Ad. Then on Sunday, which is my biggest day of the week, sales were beyond flat. Now it's like they have me clocked and my daily totals are almost always the same as the day before...very little natural variation.
Congrats on your recovery SEChecker, some of us only dream of that situation. I gave up on SEO a long time ago. I write for my users and that's it. I think perhaps if I had more time to work on new content and spent less time dwelling on watching the serps yoyo from week to to week,I might find some better results.
For now I'll have to live with this paradox of good listings, but zombie traffic.