.

No, it means that you can install it 5 times in different computers or in the same computer, after major windows updates or hardware upgrades.

After a major windows update or a hardware upgrade, your windows computer is described/coded as a new/different computer and all MQL5 Market purchases are uninstalled, so you need to install them again, consuming 1 activation.

Usually Metaquotes credits one extra activation after each major universal window update.

Additional information.

Win 10 have some issue, after win 10 update, 1 of activation will be disappeard.  

If you are using win10, you can try to set win 10 update as false.