1) I'm always getting scores between 1-5 million (since I win), usually having my kills in the 800-2500 range, losses under 200, and builds under 300. These matches take about 40min-2 hours.

On a typical YR match, I don't get over 1 million often, having kills under 1000 most of the time, and losses and builds under 200. Keep in mind these matches also only take an hour at the most (usually).

If you get 3,000 kills and win you'll have a score in the 5-6million+ range, but if you get 3,000 kills and take second, your score will be in the 3-5 million range usually.

2) So I had 3,101 kills in a match that lasted 2:20:07. My score was 6,814,801.

Then I got 3,500 kills in a match that lasted about 16 minutes, my score was just over 8 million. Only 400 more kills, but about 1/5 the time of the other match, yet I get over 1 million more points.

3) This one involving score+kill comparisons.
My brother did a match on my mod and got 5,281 kills. But probably 4,000 of them were infantry (he killed enemy based completely except for Barracks, then kept SEALs and Tanya around so he could kill every infantry they built).

Then I did a match later on (it was the match above with 3,101 kills). In that match, 2,500+ of those kills were vehicles, expensive ones too.

5,281 (cheap infantry based) kills - 6,185,463
3,101 (expensive vehicle based) kills - 6,814,801