I don't think we gameplanned to get sacks that game to be honest, between Colts having a top 5 oline and Rivers being notoriously hard to sack because his veteran experience we didn't bring pressure to bring him down. The best we could hope for, which I believe the Bills executed quite well, was to make Rivers uncomfortable and delay is processing time by a fraction of a second longer than usual.
That missed 4th down throw to Pittman? Pressure package that threw him off JUST enough that he misread and backpedalled, then threw off his back foot.
That other missed down to Pittman for a sure first and goal? Brought just enough pressure/confusion that he threw the ball a bit too late, or he thought PIttman would sit in the zone and turn upfield for the 1st instead of continuing his route.
If the other team provides outstanding protection and the quarterback reads the field quickly and gets the ball out quickly trying to bring overwhelming pressure to overcome those advantages is very risky. You have to bring too many guys to get the result you want (sack).
The less risky move is to understand that you're unlikely to sack him, but you can overcome that by creating just enough confusion/hesitation that a throw will come a fraction of a second late, he'll second guess what he's seeing for just a moment and those instances are enough to create the big play you need on 3rd down to get the stop. The margin for error is smaller, but its way less risky than trying sack a veteran QB with a fast release and outstanding protection.