On your statement that Schedule 4 request comes after officer review, it does not necessarily follow, though that was the case for some applicants that got PPR late last year. The schedule 4 for those applicants were outstanding, hence their request before the PPR were issued.
However, recently most pending files were transferred from from Accra to Hong Kong VO. What Hong Kong VO basically did was request missing schedule 4 for files received since they are actually meant to be part of submitted documents for each PNP application. They were requested irrespective of officer review already done or not.