I do think he blew it in the Philly game by not taking the points. But, I think he probably made the right call against Atlanta. By going for it Atlanta got the ball inside the 10 and was forced to punt giving us the ball on the 50 which gave the offense a really short field to get the go ahead TD. If they kick the FG, I'm not sure that Atlanta doesn't get the ball back and just keeps handing the ball the Allegiere until the clock runs out. We were down Davis, Gay, and Mathieu and had not been able to stop their run game in the 4th.
Also, the play calling inside the 10 on that drive was not good on all 4 downs. Kamara runs to the left for 8 on first down but you take the 5 yard penalty (I would have taken the run depending on the spot) and then you mess around with runs to the right and passes for 4 downs. Kubiak has done a good job calling plays, but not on that series.