I set all Resource share to 7.77%, But Einstein@Home and MilkyWay@home using Resource share of 15%

Not sure why World Community Grid (running on a iMac) is using 62.08% Resource share. Device Profiles is set to 7.77% of processor time.

I am running Bonic on a PC. Not sure why three project are using more then the other projects.
Asteroids@home using 27.69%
Rosetta@home 27.69%
World Community Grid using 27.69%

PC settings
https://photos.app.goo.gl/xZoisaMxnrTrZ6fDA

Mac Setting
https://photos.app.goo.gl/1UPkdzYQHkDi2x8r7

You can't set the percentages directly. All you can set are the absolute numbers - 100 (default), 15 and 8 for your lower priority projects. Then, BOINC adds up the numbers and converts each individual share to a percentage of the total.

Your PCs have three projects still at a share of 100, and a total of 362. On the Mac, you only have one project at 100, and a total of 162. The percentages work out different, because the totals are different.

The values can be used as approximations to percentage.
For instance, if you have 10 projects, all running at resource share 100, each project uses approximately 10% of the total run time (usually averaged over a long period of time, like months).
If a project has no WUs for months, and in the last month has WUs, the other projects priorities will lower temporarily (even though they still are at 100), and the one project will be prioritized, so that it has roughly the same amount of CPU time, as the other projects had.
This is why you can sometimes see days or even weeks of one project, before it switches to days or weeks to another project; or if yet another project doesn't appear for weeks, despite it having WUs available.