idioms - "come on as" versus "come across as"

Would you say that both sentences sound correct?

1. On the whole, I think you came ON as sincere and credible, and your soft-spoken demeanor, laced with a dash of wry humor, was quite charming.




2. On the whole, I think you came ACROSS as sincere and credible, and your soft-spoken demeanor, laced with a dash of wry humor, was quite charming.

The McGraw-Hill Dictionary of American Idioms and Phrasal Verbs seems to suggest that both phrasal verbs are synonyms:

a. come on as something:
to appear to be something; to project one's image as something. (The senator comes on as a liberal, but we all know better. He comes on as a happy guy, but he is miserable.)

b. come across like someone or something (to someone)and come across as someone or something (to someone):
to appear or seem like someone or something to other people. (You always come across like a madman to people. She comes across like the Queen of the Nile to most people who meet her.)

Your thoughts? Thanks a lot!

Answer

Despite the noted synonymous definitions, I think the tell in these phrases is is often one of connotation. A come-on, through other uses, often connotes a sinister or self-serving action or a pretence.

"You come on as if you own the joint."

"Did you come on to my sister?"

To "come off (as if)..." is also used when appropriate (not in the second example ;-) and carries a similar connotation. On the other hand, "Came across as," while not unused in a derogatory sense, doesn't usually receive that immediate inference of a con job.