Describe the bug

Value of RE macro fails with runtime exception error:

Macro did not finish.
[97] runtime exception at line 97: access violation: expected array for indexing, but found null

Appears to be related to effective_tax_rate variable -- may need to calculate value in macro instead of reading it from SAM variable.

To Reproduce

Steps to reproduce the behavior:

1. Create default PV Battery / Commercial Case
2. Click Macros and choose Value of RE System.
3. Click Run macro.