Thank you for your suggestions...
It is possible that I used a semi-gloss paint though it does appear quite glossy to my untrained eye. Whatever particular paint I used, I am certain that I used the best quality paint the store offered as that's standard for me. I brought photos and samples of the peeling paint to my preferred paint store, and the pro I spoke with seemed to know without a doubt that what I had used was a latex paint. I referred to it as glossy and he didn't correct me on that, but it's certainly possible that it could have been a semi-gloss.
Whether I used a semi-gloss or something even glossier, he showed me swatches that demonstrated the difference between finishes and he convinced me of the horrors in staying with something more glossy as it is much less forgiving of imperfections. However, considering I last painted 14 years ago, I am pleased with how well the paint did hold up aesthetically considering everything. This time around, I'll be going with the top Benjamin Moore latex in eggshell, and I'm going to keep good records of the exact paint that I use so that I won't be guessing in the future as I am now.
Based on my particular situation, the paint shop pro suggested I prep my walls in this order:
- Spot prime with oil based primer
- Apply joint compound and let dry
- Sand with pole sander including a light sanding of the entire wall/celing surface
- Spot prime with latex
- Doublecheck all patches to ensure smooth consistent finish
I peeled yesterday, but plan to go over again today to make sure I didn't miss any leftover loose paint. Being thorough is important to me. If I accidentally overlook a small amount of loose paint, say on an edge of one of the spots, is it a sure thing that it will start peeling up in a couple years or will the steps that I'm taking above dramatically minimize that risk?
After peeling and getting a better look at the plaster, I am thrilled that all my plaster seems in great condition with only a couple hairline cracks.
I welcome any other suggestions or input.