Key Detection Inaccuracy

So Im pretty new to djing and I have some questions about harmonic mixing. I use Mixed in Key 6 to determine the key of my tracks in my collection, but I've noticed that neither Mixed in Key, Traktor, or Beatport's key detection algorithms are always accurate. So I had an idea...I want to find mp3 files of all of the major and minor scales. That way I could load the track I just scanned into deck A and the corresponding scale into deck B and see if they match. If they dont I would know that the key detection was wrong. Is anyone else doing this or is there an easier way to determine if the key is correct? I watched a video of DJ Endo recently playing the scales in FM8 will the track was playing to see if they matched but I thought it would be cool to take it one step further and used recorded scales saved in my collection. Thought it might make the process a little faster.