Watch the Video Lesson:
If you ever study accurate transcriptions of guitar solos, or look at videos of players soloing using the blues scale, you may notice something that seems like an inconsistency. Sometimes, instead of using the Blue Note that’s conventionally a part of the fingering used, players slide out of position momentarily and use an alternative location for the same note. Here is an example:

Blues Scale (SFS mapped on string 6) with 2 blue note options
I will play the blue note on the left when ascending, and the one on the right when descending. If you map your pentatonics using SFS instead of shape memorization, then one of them is on SF4 and one on SF5. Here is the same thing happening in another fingering:

Blues Scale (SFS mapped on string 6) with 2 blue note options
For SFS insiders this is the fingering that occurs when you base the system on string 5. Again, the blue notes are on SF4 and SF5, just mapped on different strings.
So what’s the point of doing this? Well, there are some benefits to using both of these blue notes, but if you want you can just get rid of the one on SF5 like many people do and just simplify things. But if you do want to take advantage of both options, watch the clip from lesson 8 of SFS pentatonics, where we discuss this a little further (included in the video above).