Rise Above

It's been a little while now that I've been experiencing low-rise cakes from my oven at home. I'm trying to pinpoint the problem. It is very frustrating to work so hard, and when it comes out of the oven, you think "huh, that's it?"
I would have said it's been the last 6 months or so, but I was just rereading a post from almost 2 years ago where I have a similar complaint.
In class, I mentioned this to my chef a couple times. Here are the factors that may be suspect: 
1. Temperature- We talked about temperature, but wouldn't I recognize if it was way off because I would have burned edges, but uncooked centers? I don't have that problem.
2. Overworking the batter- I had just finished a couple weeks in class of baking cake, and tried one at home, and had the low-rise problem. I did the exact same technique, etc. It couldn't be that.
3. Not creaming for long enough- Could be, but same explanation as number 2 (above).
4. Freshness of ingredients- I had just recently bought all new ingredients for some pies I was making for a friend, so initially I ruled this out. However, chef said sometimes you just get a dull batch or whatever. She buys new baking soda and baking powder once a month, because for merely $4 you can avoid this potential problem. I had also bought a different kind of all purpose flour (King Arthur), I don't know if that made a difference.
The next two cakes I made in the oven were a flourless chocolate cake and angel food cake. Flourless tends to be low rise anyway. And angel food uses egg whites for its leavening, so I still can't say whether the new ingredients have made a difference.
5. Not allowing it to set before opening the oven to rotate the pan? Well... could be. But again, in class with other students opening and closing the oven constantly, I would have had the same problem there, but didn't.
6. Properly prepping the pan? I did switch to using vegelene spray instead of baking spray or the old fashioned way with shortening and flour. But in class, no problems with this either.

I need to get scientific and experiment with cakes, methods, temperatures, etc. I started the other night. I bought a cheap box of devil's food cake from the market (to save time and money, because I'm not even concerned about using it for anything other than helping me solve this problem). My first experiment was with allowing it to set before opening, and with the pan prep. I sprayed one pan with vegelene, and used shortening/ flour on the other. Was supposed to take 26-31 minutes, I didn't open until 26 minutes. Peaking in without opening, it was poofy. It definitely rose. The problem with this is that - it's boxed cake, and devil's food none the less. Who knows what chemistry they've put together to make it fool proof. The method was to pour into a mixer the powdered cake mix, eggs, oil and water all at the same time, and mix it on medium for 2.5 minutes. This is NOT what you do with a scratch cake.
So - I feel my results were inconclusive. The cake rose, and curiously domed significantly. Both pans, with different release methods were pretty similar.
Moving forward, I can try again with a boxed cake, maybe something like a yellow cake (something where I know how it should look). Or maybe I should flip through recipe books, find the easiest white or yellow cake that won't break the bank on ingredients and experiment with a real cake.