To me it sounds like you have a air leak somewhere between the carb and engine depending on
the outside ambient air temp. what was the temp outside on all of the your flights?
was it cold one weekend then warmer the next weekend ?when it is cold outside the engine
will want more fuel so it will be a little lean compared to flying it on a hot day.
with an air leak you get more air pulled into the engine so therefore you have to richen it.
when the air leak seals up you will be to rich,therefore you have to lean it.
I would look at the carb/reed block gaskets.
I also remember something about taking the reed block and sanding the surfaces flat on the DLE 55.
Also if your piston ring has not seated completely yet,air temp changes can have an effect with that due to
the expansion and contraction of the different metals.A lot of DLE 55 users are putting the Frank Bowman rings
in and seeing a better idle and performance gain.

just some ideas/thoughts
hope this helps
Roy G