It used to be taught for the PF to keep on hand lightly on the throttles during critical flight phases - especially final approach/landing - to know what the engines were doing, and to guard against a potential autothrottle malfunction.
Absolutely the correct technique, IMHO.
So putting the thrust levers to the firewall will give you max TO thrust for those conditions - not always wanted, needed, or even desirable for a go-around (especially with a light aircraft).
This is a new concept to me - in the few jet aircraft I have flown, EVERY go-around was flown with TO thrust until level-off. I have never heard of the option of using less than TO thrust for a go-around - what is the PM meant to answer with when you say "Check Thrust"? Not having a go, genuinely interested in this new (to me) idea.