I am definitely not Sheldon Dingwall, but I own several many Dingwalls (nearly 30) so I can only speak of my experience (and I have played few more). There is a good reason why the two basses do not carry the same model name, as well as the same price (let alone the tone).
IME Dingwall basses offer models with different tonal versions of the trademark Dingwall playability, tone and ergonomics. I can achieve similar tones by using different Dingwalls, but I cannot achieve all the tones that one Dingwall bass offers me by using another Dingwall bass. That's why I use a specific Voodoo when I play Dub and Reggae, while I use a specific Prima Artist for my Fusion projects and the FRB Z3 for my Pop/Rock group (I am knit -picking here and I know). Still I can use most any Dingwall in most any project and still be happy (not feeling let down).
The Afterburner has different specs at several important design points compared with the Voodoo. I LOVE my Afterburners (I own 5 AB's so far, three of them are really one-offs) while I love my Voodoo's, but tonewise, I do not think that they share identical tonal ballparks (they do overlap though).
Pickups are one of the crucial parts of the tone chain, and Sheldon spec-ed Barts impart a specific tone. FD-3's (and FD-1's even more) offer a departure from that tone.