It can only be a Double Foul Right?
 

I don't know why this is bothering me so much. Here's the play in order 3rd and 10 at midfield:
1- A Holds
2- Interception by B
3- Block in Back by B
4- big return....fumble....recovery by A

Without the second change of possession, in order for B to get the ball you have to decline the holding penalty .... the BIB gets accepted by rule and you go off and running from there.

I offset the fouls....two live ball fouls. Everyone bought it. But, I am now wondering if I should have offered the defense the opportunity to decline the A penalty...A then declines the BIB and gets the ball first down and 10 from deep in their own end. Based on two live ball fouls...can someone put my mind at ease? Never been in that situation before.

Thanks in advance.

You did it right. Since the team in possession at the end of the down (A) fouled prior to the last change of possession (they held), it is a double foul- replay the down from the previous spot.