Audio Research I/50

i read somewhere that it has an automatic bias.
its a bit hard to believe that you cant make a bias.
any way i asked a friend of mine, a experience technician in those amps, to check this subject.
i agree that its a bit bother, since from my experience tubes bios should be checked from time to time, even before replacing.
this subject must be checked.
2000 hours is not so much to people that use the amp frequently.
"If your amplifier is getting regular use (2+ hours a day), you should at a minimum check the bias every 3-6 months."

found this:
"Like all modern amplifiers from Audio Research, this one also has automatic bias adjustment, which makes living  with a valve amplifier much easier".
but still, i  would like to have an option to check and bias it by myself from time to time.

the question is why if it has automatic bias , you still have to bias it "by a trained technician to ensure proper operating values."
something is contradicting here ?

That is probably after you install a new tube-set.