There is some debate about this issue. The stats I have seen around deal more with the meat reaching a certain temperature than with the amount of time it's in the smoker. The theory goes that once the meat reaches X temp, the outside of the cut "closes" due to the heat, and quits accepting external flavorings.
One thing that I know for sure is that smoke flavor will continue to build on the surface of the cut as long as smoke is applied.
You didn't say what smoker you were using, but if it's a Cookshack, don't assume that just because you cannot see smoke venting from the top that you are still not building smoky flavor.
With all that said... How much are you paying for your wood chips? If the cost is minimal, don't change a thing! You said you liked the taste, appearance, and I'm assuming texture. If the cost and effort aren't an issue, go with what works for you!