An old application note from Analog Devices about configuring multiple digital potentiometers to improve resolution, accuracy and programming complexity might add-up to the mix though. Link here (PDF)
Digital potentiometers usually come with standard resistance values of 10k, 100k, and 1MW at a given number of adjustable steps. If an application requires a resistance range that falls between these values, users will most likely apply a part with a resistance larger than needed scarifying resolution. Fortunately, users can parallel, stack, or cascade multiple digital potentiometers to optimize the resolution for a given application. In this article, we will share some of the ideas that may solve the challenge.