...use 1m as the value(s).
So, if the value of $7 is 200,000 then substitute the value, in the calculation only, for 1,000,000.
awk -F, '{lhs=$6*$10;rhs=$7*$9;tot=$7+$10;sum=(lhs+rhs)/tot};{print $2,$6,$7,$9,$10,$(NF-3),$(NF-2),$(NF-1),$NF,sum}' myfile
Not entirely sure this can be done in...