Poor Spelling or Poor Hearing?

How many times have you heard a song, and then been totally amazed at the words when you read the lyrics?

I am trying to figure out if the person who printed this label thought tensor was tension, or if they just thought is was just spelled this way. I wonder if the addition of 'high' was a marketing ploy.
A third possibility: I have been away from the world of emergency medicine for over 10 years. Who knows what they have come up with!