The data in Message Analytics (accessible via the Messages tab) will only show data for the currently active variants in your message groups. It hides analytics for variants that used to be sent for the message but have since been removed.
However, the “Sent” column will still reflect all messages sent, which is why they may not add up if you’ve deleted variants for the message. Since the “Sent” number is a total, it also will count users multiple times if the received a push notification to more than one device token:
If you have removed variants, you can get a more complete picture of your message data in Insights, where you can view Notifications Sent Events for all variants.