I can't speak about half speed recordings but I can offer some advice on your TT. I also have a Pioneer PL-530 which I bought new many years ago. Due to the age of these tables it may have been very long, if ever, the speed pots were cleaned or inspected. Whether playing on 33 or 45 speed the movement of the dots from the strobe should remain still while playing a record. The speed may change ever so slightly when the stylus drops on the record surface. A minor adjustment in speed can compensate for that.
Not saying that the tech that analyzed your table is incompetent but I have address speed fluctuations on this table before. If not needing replacement, the speed pot(s) may just need cleaning. Deoxit will do the job but removal of the bottom is required to do it correctly. Good luck.
Not saying that the tech that analyzed your table is incompetent but I have address speed fluctuations on this table before. If not needing replacement, the speed pot(s) may just need cleaning. Deoxit will do the job but removal of the bottom is required to do it correctly. Good luck.