Hello,
been a while since the last post, i guess. I have the same problem with 5.5. and tried all kinds of workarounds. It all results in the fact, that:
a) CS 5.5 with Mercury Engine enabled is not able to deinterlace anymore, the results are still interlaced, not matter what has been set in the export settings.
b) CS 5.5 with ME disabled gets poor and blur result if interlaced material is deinterlaced.
Both a) and b) are working on CS 5.03
Testes with PAL 16:9 interlaced DV source and Export to MP4 progressive.
best,
Jörg