I am sure it is the bulb that converts the power down to DC. With a DC circuit, resistance is all that's required to reduce voltage. At 14 watts, it doesn't take much capacity to cut the voltage. Seems there is a point at which the reduced voltage reaches a point where some bulbs begin to flicker, so the dimmers are designed not to go down to zero and continuously leak about 10 percent of the total power. I ordered some commercial resistor devices that promise to prevent the flickering, probably by automatically cutting off all power at the flicker point. Hopefully that will solve the problem.
Otherwise, it seems there are two ways to handle this: 1) learn to slide the dimmers down and click the off switch at that point, or 2) replace the bulbs with incandescent models, which filaments stop glowing at a certain point.
Unless, of course, someone here has a solution.
The more I do, the less I accomplish.