Nightowl
Your playing isn't "below standard," you're exactly right on the money for your playing level. You get the feedback you deserve based on your playing, not because anyone is fluffing you. That would be a cruel thing to do to anyone.
The arrangements in the method books are meant to teach, not play for entertainment. That's why they're awkward and don't sound very good. You only need to practice them until you can play them all the way through and have learned the technique they're teaching with that piece. That means being able to play 75-80% of a piece without mistakes, at tempo, is good enough to move on.
I believe that a piano student should be doing 3 things:
- Their lesson pieces on a weekly or semi monthly basis, 75-80% learned and played to tempo.
- A performance piece that can be learned and polished to PW/PT recital submission quality within 2-3 months.
- A stretch piece that can take as long as 6-8 months to learn and polish which can be played without mistakes at a "formal" recital. (Not that you have to do that, just be able to play it to that standard.)
You're trying to make your lessons pieces into #2 and #3. It's not necessary or desirable to do that. Learn what the lesson piece teaches and move on at a consistent pace. For #2; find something just a bit beyond where you are and split 2 or 3 sessions per week for both your lesson and this piece. The stretch piece is supposed to be special and something you really want to learn to play. You have to do a little bit of research to find something in this category because you have to gauge your playing progress and then project where you think you'll be in 5-6 months so you will have most of the skills to play the piece you select. This is hard but not impossible. You have to add 1 or 2 extra sessions per week for this one.
So, a plan emerges. You're (I think) around midway through book 2. Look at the last piece in the book. You can start learning the original score for that if you want, or find something equal to it by checking all of the internet sources for similar grade level pieces. That's your #3. You have 6-8 months to learn it. By the time you do, you'll be at or near the end of your Alfred's book so the timing will be right.
Now look through your supplemental books and find something midway through one of those. That's your #2 piece. This should be equivalent to 3 or 4 lessons pieces ahead of where you are. You can also check the various internet sources for grade level stuff to find something in this range if there's nothing appealing in your supplemental books.
If you get stuck, ask for recommendations. There is so much knowledge here that not taking advantage of it is almost a crime. For instance, I think you could easily learn the original score of Bach's Minuet in G Major (Petzold) by Thanksgiving if you put your mind to it, certainly by the end of the year even if you got lazy in your practice sessions.
This got too long winded. Sorry.