I see. You are using continuous controllers that have too many events per quarter note to quantize.
This probably won't help you, but I actually add pitch bend and volume swells by highlighting a specific range and inserting controllers. That way the first and last messages are in the right place and the other values are distributed evenly.
The only problem is that Sonar puts in too many messages—like 8 per tick, which is ridiculous. So, I highlight all the controller messages EXCEPT the first one and last one and then use then Thin Controller or Thin Pitch Wheel CAL. I usually have to set the CAL program to remove every second event and, even then, I may run it 2 or 3 times.
You don't have to thin them out, but too many pitch bend messages can really bog down your CPU and I don't think anyone can hear the difference.
This is tedious but I have done it so many years that I have gotten pretty fast. I already have ideas about how far ahead of the beat a pitch bend should start and how long after it should continue. Few players end up on the final pitch exactly on the beat. A lot of keyboard players using wheels tend to bend faster than a guitarist would.