I had the reverse of your situation. I'm D/S and always finish ~17th (newbie/noob). If my DR really drops I get matched with A/A. This increases strength of field for me, but decreases it for you. I got 197 points for finishing 17th.
However, in another race exclusively with D/S drivers I also got 17th place and got 7 points.
In your situation if you're A/S or B/S you won't get matched with D/S drivers. If you are A/A you will and your points will suffer. SR doesn't seem to be a direct factor in point scoring, but it is a strong factor in matchmaking, resulting in a lower strength of field, but only if you're unlucky enough to end up in the split that mixes D/S with A/A drivers. This is a problem for very weak D/S drivers or really strong A/A drivers and the chance is bigger unpopular races. They shouldn't mix D/S and A/A in these races and fix their matchmaking algorithm.