quad bias control ?

anyone have this installed?
im referring to this  dynakit  2x2 bias adjustment add on at
dynakitparts.com shop bias-balance-control-kit

is there any notable differences between tubes that are supposed to be matched?
and if they are not matched- is there usually a notable difference?
personally i like the idea of the kit.
also id like to know,outside of bias voltage, is there another voltage that varies as the amp is running that you might want to "monitor" with a gauge or a indicator light. to be able to avoid calamity if possible. if you were the kind of person who pushes your amp?
such as, i am that guy

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ok so its a fixed resistor evening voltage voltage x 2 thing that keeps transformer voltage in check?
i was thinking the 4 way bios// sorry.bias may be beneficial in using two different but cross referenced tubes for getting a "best of both worlds thing"like for the liking of 2 different tubes that sound different in the amp, -blending.
..now...say your resister is 1.56! as i understand it the bios setting revolves around this because of the resistor that is suppose to have that value. because of ohms law.ie.it takes 1 volt to get 1 ampere through a 1 ohm resistor? so what if that resistor is not spot on 1.56. what if it were 1.49 . would you then set the bias to 1.49?


edit,-in my haste id forgotten 1.56 is the old battery reference voltage at the 10k ohm right?
so i re-ask..if the resistor was not quite 10k, say it was 9.6k, would i set the bios to 1.49 ?

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FYI:

BIOS: Basic Input Output System. This is the code that some computers use to establish fundamental operation at power-on, before the operating system is loaded.

bios: plural form of the informal word sometimes used in place of "biography".

bias: Usually refers to a dc voltage or dc current used to set the zero-signal operating point of an amplifier.

Individual bias potentiometers in a stereo push-pull tube amplifier reduces the amplifier's dependency on complementary tube pair matching. Note that two tubes that produce matching cathode currents with identical bias applied may or may not be matched at other operating points along their characteristic curves.

i know this beede, thanks, i am more computer literate than tube audio literate. i was use to the word/sounlike bios because of my familiarity with firmware/software. lol i realised what i was doing earlier today. infact. the start of this thread i spelled it correctly.
and yet i still misspelled it afterwards. lol, go figure