Tactics for high score on Plague Inc
PAX-12 DNA Sequence: Complex
Difficulty: Normal
Disease Type: Parasite
Time: 1050 days
Cure Progress: 20% complete
Score Total: 36630
4/5 bio's
My tactic was basically the same. I also believe you get more bio's on brutal. Except I go for coma as well to make it harder to cure. Along with paralysis and paranoia, coming from the insomnia line mainly.
But to answer your question, I believe it is mainly calculated by cure progress. Just did it again in 635 days, but 52% cure progress (less resistance upgrade more lethality) and got 12k score with 3 bio's.
A test on brutal, also testing DNA points left over:
Complex
Brutal
Bacteria
2018 days
98% complete
6230pts
3bio's
To me this says that cure progress is still most important, as I had nearly 60 DNA points left over (it was quite hard to do that on brutal btw, barely did it (first try though ;)