Should I retake SAT Subject Tests?

I took Math Level 2, Biology, and US History in June and scored a 630, 640, and 670. I’m thinking about taking Math Level 1 and retaking Math Level 2 and Biology in December. Would this be a good idea if the highest I think I’ll score on my Math 2 and Biology retakes is 700 in each? Should I take Math 1? I’m not sure if those 50 or so extra points would be worth retaking for. Any suggestions would be appreciated.