Let's face it, if all you played was one scale all of the time, it would get boring. This "Add-One" gives more color to it.
This time, I will talk about adding a b2. This gives it the Phrygian sound, for those less inclined to technical music terms. it gives a "Spanish" sound.
The Phrygian is used quite frequently in heavy metal (as well as Spanish music). So, when you add this b2, the pentatonic sounds darker and more exotic.
Here are 5 positions of this scale.
| 
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| R | 4 | b7 | b3 | 5 | R | 
| b2 | 
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 | b2 | 
| 
 | 5 | R | 4 | 
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| b3 | 
 | b2 | 
 | b7 | b3 | 
| 
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| 
 | 5 | R | 4 | 
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| b3 | 
 | b2 | 
 | b7 | b3 | 
| 
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 | 5 | 
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| 4 | b7 | b3 | 
 | R | 4 | 
| 
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 | b2 | 
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| 
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| 
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 | 5 | 
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| 4 | b7 | b3 | 
 | R | 4 | 
| 
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 | b2 | 
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| 5 | R | 4 | b7 | 
 | 5 | 
| 
 | b2 | 
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 | b3 | 
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| 
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| 5 | R | 4 | b7 | 
 | 5 | 
| 
 | b2 | 
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 | 4 | 
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| 
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 | 5 | R | 
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| b7 | b3 | 
 | b2 | 5 | b7 | 
| 
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| 
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 | 5 | R | 
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| b7 | b3 | 
 | b2 | 4 | b7 | 
| 
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| R | 4 | b7 | b3 | 5 | R | 
| b2 | 
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 | b2 | 
| 
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I like this touch because you can add that b2 by hammer-ons and half-step bends. In other words, they are easy to get to.
My two cents.
