Commas Separating Parenthetical Phrases

If there is a complete (independent) or incomplete (dependent) clause following the parenthetical phrase, we would do this, right?

D you agree w/the punctuation in every sentence below?

[i]It’s been a while and, if I may, I would like to ask a question regarding introductory and interrupting expressions.

I didn’t think he would attend the banquet and, quite frankly, I was surprised by that he did.

John Doe said he thought the prices were a little steep and, to be honest with you, they are.

John went to the party and, to be quite blunt, he acted like a buffoon.[/i]

[i]SAME AS ABOVE SENTENCE WITH COMMAS? John went to the party and, to be quite blunt, acted like a buffoon.

We can bill you on our customary terms or, if you prefer, we can charge your credit card.[/i] (Independent clause follows parenthetical.)

We can bill you on our customary terms or, if you prefer, can charge your credit card. (Dependent clause follows parenthetical.)

I believe that all of the above sentences are punctuated correctly irrespective of whether or not an independent/dependent clause follows the parenthetical. Is this so?

Thank you.

I;d agree.
In number 2, the final phrase should be “… I was surprised that he did.” (no ‘by’). However this does not affect the punctuation or vice versa.