I may be wrong, but I thought you had said that the ST's black level will drop a bit after a few hundred hours, then rise back to it's original reading. (i.e. the 55ST50 going from 0.0049 to 0.0026 and back) If I'm remembering correctly.
Do you anticipate the 65ST50-or all 2012 Panasonics-behaving the same way? Thanks.