Override Product level OIR with Organisation level OIR

In the organisation context we have 568 products, for which Product level OIRs have been such that Numbers are auto generated for WTPart (it has final = "false" for Numbering). But now the requirement is such that for all products the numbering should be manual. I created an OIR at Org level with final = "true" value and set auto numbering off, but still numbering is auto generated only. Is there some way to override the product level OIR at Org/Site level so that we can have manual numbering, as going manually and changing OIRs for all products is a tedious job.