Correct. According to the documentation:
A computer that runs on a public cloud is assigned the number of PVUs that is specified in the BigFix Eligible Public Cloud BYOSL policy. Information about the assigned number of PVUs is displayed on the Computers report after the next capacity scan and import of data. PVU consumption for the software that is installed on such a computer is properly calculated.
Unfortunately, the policy link in the documentation just points to the Flexnet portal login. It seems likely that the BFI Import process has this calculation built into the code. I don’t have any cloud computers to test with, so I don’t know for certain. Do you see anything in your log file that might be related? I found an entry “INFO: ETL from VUTImport: Start”.
What does your Computers report show for PVU count for your Public Cloud computers?