what does an unadjusted IP symptoms be?

[Solly]

ideally 8.5 bars, specs say anything between 8.4 and 8.6 bars would be ok.
Using my IP gauage on a brand new out of the box regulator, it gave me something around 8.8 bars

 

[halocline]

What's .2 bar, about 3 PSI? Don't worry about it, it's likely your gauge isn't that accurate to begin with, unless you have an expensive one. Go on a couple of dives and see if it drops a little as the seat/orifice get mated a little more completely.

Does this thing have kind of a spherical seat? Something that's supposed to behave ideally for air flow around the seat/orifice and also be very resistant to wear?

 

[Solly]

What's .2 bar, about 3 PSI? Don't worry about it, it's likely your gauge isn't that accurate to begin with, unless you have an expensive one. Go on a couple of dives and see if it drops a little as the seat/orifice get mated a little more completely.

Does this thing have kind of a spherical seat? Something that's supposed to behave ideally for air flow around the seat/orifice and also be very resistant to wear?

yep, I guess it is the guage not very well calibrated and no, after some dives it is still the same...
about the second question, I think I need to have some training on reg servicing, I am not sure I understand your Q... what is a seat?

 

[cbmech2]

I can't recall what regulator exactly you have. If I remember correctly it was a Mares? The seat is a mating surface to either the knife edge on the piston or in a diaphragm type a sometimes removable crown. Think of it like a normal, everyday water hose nozzle that allows water to pass, excpet in the case of a regulator it is of course compressed air. If these two surfaces do not wear in evenly together there will be leakage problems that cause the IP to rise.