In the C130 world you need 800 hrs as a copilot to be eligible for AC upgrade. Your unit would work an AC slot for you around the time it was predicted you would have 800 hrs. Rank pretty much had nothing to do with it. IP school was different, with rank playing a very big factor. Units would work very hard to get a guy coming up on a majors board into and out of IP school before his board so he could have the "MWS IP" stamp on his record.
Your AC school date could be delayed if your unit didnt think you were ready, for whatever reason.