JT250: Pretty certain that this is a mistype. Looking at KSLC I can see that they list
a disc JT205 with exactly the same track listing.
JT365: No idea. I can see that KSLC list it but can't find a sniff of its' existence on
the web. I was sent what purported to be the disc but some of the tracks were
clearly Pocket Songs and most of the others were by other manufacturers; except
for track 9 - which was clearly JT - but I can't find another JT disc with that track.
JT393: I could be very very wrong here but I reckon that it's a compilation of
already-issued Sinatra discs. Likely suspects would be the eight discs from JT371
to JT378 which were issued (numerically) shortly before.
5150: ?? Not sure what that figure is, your attached screenshot clearly says 4895.
I have 4860 ZIPfiles in my JT directory which is only 35 difference and if you take
into account your listing of jt397 twice (with and without track 9), that brings your
4895 down to 4884 - only 24 more than my JTzips; and then I have 116 JPEGs and
21 TXT files - your directories may be similar.
We may have come some way to sorting the JT directory out