My AT150MLX Cartridge has been misaligned for 4 years

The stylus just has 4 years of specific stylus wear due to the alignment. It sounds better now, just go with it.
If it were aligned according to the jig 4 years ago, it would just now be worn based on that.

Try a Rega cart next replacement time. No alignment necessary.

Should I spend the next 100 hours allowing break-in for the tubes, things still seem bright but then again that could be the Thiels LOL... But they are so nice to listen too.

What do you mean my "misaligned" ?
This cartridge have MicroLine stylus and this stylus is very sensitive to VTF, VTA and Azimuth.

What was misaligned then ?

After realigning the cartridge things are soooo much better but not perfect.

What is not perfect if everything is sooo good ?

At least 3 basic methods can be used: Baerwalf, Lofrgen and Stevenson ... (not to mention some more). They are all correct! But tonearm designer using just one for his particular tonearm.

If you think your previous settings were wrong maybe you’re wrong, maybe it was just another alignment method? It it was wrong then why in 4 years you never noticed any problem with sound quality ? 

You have probably damaged your records. If a cartridge mistracks - the groove is permanently damaged.

You might want to change your moniker.