Tones from Neck and Mouthpiece

Hi all. I have been reading a lot of the articles on here, what a great website!

I'm a bit of a beginner at this (alto sax), and I want to learn things correctly. I read the article about proper emboushure and was trying to get my moutpiece and neck to produce the recommended A880 tone. I have a KORG choromatic tuner that I use for violin, and it's been tested against other tuners so I know it's accurate. I cannot get the neck to produce the A880, it will make a G# all day long. If I stuff the mouthpiece further into the cork, I can get a "low" A880, but then the instrument plays too sharp, and doesn't sound right, I get some oscillations and "phasing". The correct position (for this sax) for the mouthpiece on the cork is where the neck (alone) makes the G#.

I've been able to form my emboushure in order to get a nice, round, full G# using this technique, but can't get the recommended tone of A880.

Any suggestions? Is this a big deal?

the instrument is a YAS 23.

thanks

Dana