If v5 project has `[billingAccountId](https://github.com/topcoder-platform/tc-project-service/blob/develop/src/models/project.js#L10)` in the payload, it should be synced to the legacy project https://github.com/topcoder-platform/legacy-project-processor/blob/develop/src/services/ProcessorService.js#L189 and https://github.com/topcoder-platform/legacy-project-processor/blob/develop/src/services/ProcessorService.js#L359.