Welcome MitchD. If you stick around these boards you'll soon realize there are some really smart people lurking around, and I'm not one of them. But I do have a PatDually and I work on my own bows. I would not say that a dually is "considerably" harder to service than a solo. I would say that a dually has two cams and they need to be in sync like all dual cam bows. If your dually has the pre-stretched O2 strings from the factory or Winner's Choice strings there shouldnt be much settling/stretching after the first couple weeks of shooting. If the string stretches from it's initial length then your cams will get out of sync. You can tell by drawing back slowly and watching the cams bottom out. They should both roll over and bottom out at the exact same time, if one hits the wall before the other one, your cams are out of sync. You can still shoot your bow like this but your groups wont be as tight, expect some unexplained up/down errors. Having the bow serviced is simple for any bow shop and fairly simple for any bow shooter with a bow press or portable cable bow press. I figured it out just by reading these boards (search for: bow tuning, cam timing etc) and just looking at the bow.

I think it's important to point out that the solo cam bow is not without issues either. Many people believe that a solo cam bow cant get out of time. Not true. A solo cam has a sweet spot. It needs to set at a certain position when the bow is at rest, if the string or cables stretch it will leave this position and change the performance of the bow. Just like the dual cam bow you can shoot it like this, it's just not performing to it's full potential.

Hope this helps