I dont think its working right.

For example "Dispute on Risa" mission

Overall ranking: 5 Stars.

Breakdown of voting:

5 * 1
4* 2
3* 7
2* 7
1* 5

My mission, "Frayed Edges V2.1:

Overall ranking: 1 1/4 stars

Breakdown of voting:

5*
4*
3* 2
2*
1*

Not sure how this is working right?

On a mission I created I saw the average of the stars was correct. Though I have noticed the wonkiness you have described when searching for other missions. A lot of missions rated mostly 3 stars or less pop up in "Top Rated" searches for me.

Yeah, the formula for calculating the "average" seems off somehow.