"As in" is usually used to cite an example. When you are talking on the telephone, to clarify the spelling of a name, for example, you can say "SMITH: 's' as in 'Sierra', 'm' as in 'Mike', 'i' as in 'indigo'," etc.
"Mr. Angelina Jolie? As in Brad Pitt?"
++++
"As of" is usually used to indicate time. "As of midnight tonight, it is Winter."
"As of now, nobody knows if he is telling the truth or not."
++++
"As with" can also be written "as is the case with": Writing about someone, just as with/ as is the case with painting, is an extraordinarily
intimate process. (means "similarly to")