found a bug in refactoring SDR that affected exports by a couple of percent

git-svn-id: svn://scm.naturalcapitalproject.org/svn/invest-test-data@72 a1e471e8-3ae1-4eeb-aa86-f41caf2650e8

sdr/agg_results_base.csv

-0,4240170.273,306.6116697,17907.82498
-1,9919849.897,875.2002978,38060.69991
-2,1438681.143,116.3305344,5646.608816
+0,4205665.78066754,298.803914701289,17528.9487579054
+1,9905725.29612588,820.701244845831,36717.3268693127
+2,1436742.72583218,115.891340147502,5630.61293952864
\ No newline at end of file

sdr/agg_results_drainage.csv

-0,4240225.399,251.4848014,15706.01731
-1,9920037.549,687.5514761,32091.20565
-2,1438708.765,88.70853646,4650.648898
+0,4205716.12642359,248.457501197656,15530.8576815141
+1,9905883.66363705,662.336518818982,31352.0518414195
+2,1436770.21568342,88.4009829482511,4639.92787431044
\ No newline at end of file