Half speed masters. Are they worth the extra scratch?

The first pix I saw of the PL530 only showed 1 line of squares on the platter, so I thought that's how they were made. Subsequent pix show 4 lines of squares. You should be able to get one of them to be stationary at 45 rpm. Look at MC's system, he's probably a 1%er in the audio world. Very good share MC, knowledge is good.

   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.

Half speed halves the frequency range so it only goes up to 10kHZ rather than 20kHz and it can be cut far more accurately.

Having said that, just play your media at the stated speed and enjoy the improvement.

Funny this would be brought up.  Over the weekend my pals and I compared the Mofi Original Master Copy vinyl vs the half speed remaster vinyl vs the Mofi SACD vs the Qobuz version of Brothers in Arms. Our group decided the Mofi vinyl was slightly better than the half speed remaster but both the Mofi vinyl and half speed remaster are significantly better than the other options. 

Half-Speed and other Audiophile grade vinyl is worth it if the original record was a well engineered recording.  I have some rock and jazz; like Steely Dan's "Aja" or John Klemmer's "Touch" on half-speed master vinyl that will make you weep at how much better it makes an already outstanding record sound.

I also have a few master versions that just reveal a poorly recorded original session. Its all about the source, but unfortunately you can only discern the difference between good and just OK by trying it out.  There may be master reviews on Discogs or some other vinyl source (any body know a good reference source for master recording reviews?  Not just some deletant comments, like my opinion).

In short, generally I find if the original version was great to listen to; then the half-speed or master recording will be an even better version and worth the premium.