I can't tell you why mine are different. Average shots per game usually range from 15-30 shot for the AI team and 20-35 for my team, depending on the team and how good or bad they are, or how good or bad that I'm playing. My team GAPG is below 2.00 as well for my season at 54 games (so I'm somehow getting very good goaltending from both goalies). I don't change a ton of the sliders and play on superstar difficulty.
There is games where the AI goalie or mine will allow 3 goals on 6 shots - it can either go that they settle down and end the game with 20+ shots and not let anymore in or let in another 1 or 2 and I pull them.
Its hard to determine what goalies can or will save in game or in real hockey. How many times do you see goalies get beat on the post cause they are not hugging it or moved for a second before the shot was made.
I am not saying the Goalies are amazing or perfect. I was just able to find a way (after years and years of adjusting sliders and difficulty) that worked for me and how I play hockey in NHL.