Counter Templates created after Item Instances associations has been created

I have created some new counter templates recently and associated them to the Item contained within a grouping. However we do already have item instances for this item and the Counter templates are not showing on the Item instances that have already been created. If I create a new Item Instance the templates will show on the counters however we need the templates to show on existing instances because we are now a usage contract on a Instance that we already have recorded in Installed Base.