Cedahlia, two good questions.
1. There is a function for formatting Gantt views that is specific to PWA, and are not Microsoft Project views. Unfortunately, if I understand your question correctly, I don’t believe you can setup a progress bar for summary tasks. I didn’t test it, but am only assuming from looking at the options.
2. The % Complete progress is based on duration, not work, and can sometimes not line up exactly as you might want. For instance, if you had more total duration in the first half of a summary rollup duration than the second half of the duration, the summary progress might show slightly off a bit. That’s the way it works. It is based on the duration complete, not the Status date.
Probably not the news you were looking for, but I hope it at least helps in understanding.