Whats going on here? You say that you have the stock 14/12 jet in your 14 phva? That doesnt make sense, the jets are not interchangeable, the phva takes 6mm jets, the SHA take 5mm.
You cannot just slap a 14/12 or 15/15 SHA onto the A55, the intake will not accept it. You would need to craft a spigot so the SHA can be held by the rubber intake coupler.
You should thoroughly clean and tune the PHVA 14 you have instead, its a fantastic carb. Stock cylinder with the 14phva and the stock unmodified airbox and a biturbo should land you around 57-58 main jet. With a metal mesh air filter, somewhere around 62-65, no air filter at all somewhere around 68 In my experience