Threshold 4000

I have owned this classic, Class A creation of Nelson Pass for about 40 years.  I had it redone/updated about 20 y ago by Jon Soderberg , Vintage Amp Repair, and have been very please with it ever since.  It still sounds great, but am thinking of having it done again, as it has been at least another 20y....I could send it to Threshold, who no longer is associated with Nelson Pass.  They want about 50% less to do it than Soderberg, but, frankly, I am not sure to trust them.....any thoughts form my cyber audio friends?
If you got 20 years out of it from Jon's last update, at least if you send it to him again he'll know what can be left alone and what needs replacement, and he makes his own updates.  I'd also be asking Threshold why it's 50% less cost, are the parts of equality quality by today's improved standards and updates for another 20+years!