Nope actually, allow me to explain:
David Mendel's father began planning two Wyvern projects before the now formed Wyvern AR in order to compete on his own without a team. He wanted to be the first ever solo wipeout pilot. So David's father began the XAF-54 in 2054 when he was just a engineer for Feisar, but he never did achieve this dream after he became a pilot for Feisar that no one really knew. Sadly so he had to cancel the XAF-54 project. But when David's father died in the F9000 Mendel decided to complete the XAF-54 now to compete after Falon's betrayal.
Does that clear it up a bit?