CPA is an acronym for Cost per Acquisition.
Every time a user reaches a Conversion point, this is also known as an Acquisition. Another term for Cost per Acquisition is Cost per Conversion.
CPA = Cost / (Sum of all Macro Conversions + Sum of all Micro Conversions)
Since we measure all Macro and Micro Conversions, if you are primarily interested in measuring the CPA of a specific Macro-Conversion, ask to get this specific CPA included in your monthly report.