String Indentation on Saddle

I've changed strings 5 or 6 times on my new acoustic and I've noticed small indentations where they cross the tusq saddle, it's a compensated saddle and being a newbie I always assumed this was "hard stuff". The only reason I ask is I have a hum at the saddle on the G string and the indentation is considerably deeper there than the rest of the strings.
Are the indentations normal or am I being too fussy here. I ordered a bone semi- finished saddle on line and will be installing that before I take it for it's "setup" or should I let the setup guy do that, any suggestions would be appreciated.