Difference in Program Opportunity Analysis Report and Opportunity Analysis Report

In RCE tool for reporting in if I look at a Program Opportunity Analysis Report for total Opps created in 2019 and also at the Opportunity Analysis Report for Total Opps created in 2019  (all having the same filters, i get different totals: 3196 Opps at program level and 5335 at Opp report level.)

The question is : Does Marketo not attribute all Marketing Influenced Opportunity to Programs?  if not, how is deciding that an Opportunity is Marketing Influenced for those that are not linked to Programs?

We have the Implicit Attribution level, does the attribution level have anything to do with the marketing influenced decision?