This is just speculation, but Chicago was greatly influenced by the Genovese crime family. They could have influenced him to want to use the traditional ceremony. Ricca died around the time that Aiuppa became boss and was going senile before that, according to some people who knew him. Maybe he was the one who wanted to maintain the informal version and with him out of the picture there was no one to prevent Aiuppa from doing it his way. Accardo, who like Aiuppa had Sicilian parents, probably didn't care either way but surely gave his approval. That's my best guess for now, but maybe someone else has a better one.

If they werent made using a traditional ceremony, how was a soldier on record?

Back in the days the Outfit had an induction ceremony.There were no pricking fingers and burning saints,it was just a pure simple dinner gathering,just to be introduced to the guys in the organization and to be recognized.There are even some reoprts that some guys were made just by telling them something like "you are now with us" or "right now you are one of us" and thats it.Burning saints and stuff is a more of a traditional Italian mafia way of induction,back in the old days the Outfit was not a mafia type of organization.They were more of a organized crime gang because they also had a non-italian faction in the organization.Dont know why Aiuppa brought the old traditional way...maybe he wanted to change the ways of the Outfit because he was more of a traditional boss like the ones in New York..who knows...maybe he wanted to change the ways of Giancana because he disliked him ...im just guessing.I dont belive that the Genoveses had anything to do with it because the Outfit and the Genovese crime family had connections since the 1930's.Nitti,Ricca,Campagna,Giancana and not even Accardo had any traditional ways of inductions.Theres also a rumour that Luciano also didnt appreciate the traditional making ceremony but maybe im wrong.

@GaryMartin Ricca was a diabetic and started having problems in his early 70's i think.He had a some kind of a stroke and allegedly became senile.He walked around the parks alone and usually spent his days at the O'Hara airport.There are also reports saying that Ricca was faking it but i really doubt it since he had many problems with diabetes.I think the right answer would be 1967

Walking around the O'Hare airport was my reference point.

Over the years, i came(for me) to this conclusion:

-there was no induction ceremony as long as giancana was top-boss
-as aiuppa took over, he started making guys with the ceremony
-the ceremony was buried with aiuppa.

that would explain why some still claim there was an ceremony while old gangsters still tell you "if you know anything about chicago you know that there is no ceremony".

but thats without big research behind, just what i've read and heard on the fly..