The 6 draw and 6 bend are not actually included in the standard blues scale. I had them included in the past, as a bit of a cheat, to introduce the idea of using those notes. However, this time around I decided to keep it legit, and true to the classic scale. Having said that, you can definitely use those notes when improvising, if it sounds right!
It’s called playing ‘out’ and i think it works well in a lot of situations. It’s kinda like using the 3rd position blues scale over the 5 chord in a 12 bar progression, which would be the correct way of ‘thinking’ about it.. I discuss that idea more at the end of the intermediate course at #20 when we use the 1st position blues scale over the 4 chord 🙂
Basically if it sounds good, you can play it, but the classic scale is there to keep you on track!