Your problem is that because the only difference between the events is that the previous events have to be true for the next one to happen, once 'Find 1' becomes true, 'Find 2' immediately becomes true, and once 'Find 2' becomes true, 'Find 3' becomes true. So all 3 messages will be displayed whenever any of the cargoes are scanned.
What you can do if you have enough events to spare, is to have 3 events for each message, dealing with only one cargo at a time instead of lumping all 3 together. The 'not' operant can help you make sure each event applies to only one possible combination of known cargo. All this is doable in retail FRED. Another possibility is to mess around with variables, which is neater, but some people have a hard time with them.