Im going to go out on a limb here Fuji and say that this question is going to get me kicked in the nuts. lol
this is more of a check on learning so correct me if im wrong. The AFRs are rather more "important" then the EGTs. Mainly because of temp range for the EGTs is so vast and vary from one engine to another. One engine will be happy at 1350* while another motor same mods will be more happy at 1500*. Also the location of the tuning shop is a factory in the EGT. The AFRs dont have that wide of a range to a "happy median" optimal between 12-13.5 to 1.
Have I dun good? lol
AFR's are important but EGT's are just as important globally when you look at the whole picture.You use your EGT to gauge the safety of the tune and maintaining a range is what you want. I keep saying this... when you tune you need to
A) look at every thing together, AFR, Timing and Boost. and use EGT to gauge the result.
B) understand the relationship between them all.
C) Know what each one does both individually and together and why you are running them at the levels you choose to.
This is why I laugh at people who say "You are running way to lean" and not looking at everything else to understand what is really going on (This includes hardware like cam, compression and heads). Or why it is very rich and super low timing while spooling.
You need to formulate your question to see how he understands these relationships. Also most tuners are on a time constraint and they don't have the luxury that we in the DIY community do to be very precise. I use to believe that most tuners where "Sledge Hammer" tuners until I witnessed one in particular. I now refer to the method simply as "Quick Tuning" but only when performed by a tuner that understands the relationships. If they don't then I call them sledge hammer tuners.
To be honest there are to many questions that can be taken out of context to make the tuner sound like he doesn't know what he is doing. You may want to gauge his ability on customer reviews... What does his clientele think of him?