Outlook Add in Opportunity Button question

Concerning  Opportunities, NS documentation states the NS/ Outlook Add in only looks at the actual prospect/lead/customer email address to match the email address of the email you want to save into NS.
My sales team tells me they oft times have multiple people they are dealing with on multiple opportunities for the same Customer.  However, according to NS, the only way to automatically display the opportunity radio button is to match the actual customer record.
This does not seem to make sense, as all other Add in items search the Customer Contacts,, not the actual customer record.
Has anyone experienced this, and if so, how have you handled this? My sales team says the opportunity used to search on the contact fields of the customer, but now does not.