Anal was something that never really interested me so I never looked on profiles for it. Then one afternoon I was with a lady and while things didn't get off to a great start as I had to wait over half an hour for various reasons she was definitely trying to make it up to me. (I don't think it was her fault the appointment was delayed as I could hear her frustration on the phone)
She said a few times "I want you to fcuk my ass" but I stiil wasn't mad on the idea. She then turned and asked did I want to do it? I told her I had never done it before to which she replied - "well, now I definitly want you to fcuk my ass"! "I am taking your virginity" LOL
So who was I to argue and I had my first try at anal
She does advertise anal and there was no extra charge!
I can see though why many do charge extra as not many ladies offer it so if is a sort of premium service.
There is also the issue where a ladies ass is not designed to be fcuked all day long so an additional charge might mean that every client won't want it!