My take is basically what Applelight said. There's a lot of overlap in the elements in general, but when you tie it to their personalities I think it makes more sense as is.
Take honesty, for instance. Rainbow Dash
can be
Brutally Honest, but at the same time she doesn't really have any compunctions about lying either. I mean, compare her and Applejack in "Party of One". She obviously didn't really feel too bad about lying to Pinkie about the party, whereas AJ was obviously struggling with it.
I think it even applies to how honest they are with themselves (or about themselves). RD is
constantly blustering about how awesome she is even though she very often doubts her own abilities. She's attempting to deceive herself into thinking she's really as awesome as she claims to be when she doesn't quite believe it herself.
On the other hand, when AJ makes that sort of claim about herself, whether or not it's accurate, she actually believes it. Case in point, in Applebuck Season and The Last Roundup, she honestly believes that she has the capability to do what she sets out to do. Her motivation is less "I have to help everypony" and more "I
said I was gonna help everypony so I'm going to". That's why in Applebuck Season she kept trying to help long after the point she became a liability. She said she was gonna do something, so she's gonna do it, regardless of whether it benefits anyone.