Slow Progress in Colored Pencil

I've started a new colored pencil piece, and after working in oil for so long, I am surprised at how slowly I am progressing. I work in layers in order to achieve the complex yet subtle skin tones, and typically start in darker colors, working toward mid-tones, and finishing with the lightest colors. I repeat this process many times throughout the drawing, as needed.

Here are a few snapshots of my progress thus far. The first is the drawing with only dark umber. The next two shots have some red and blue added. In the final photo, I have decided to start working the mid-tones and lights one section at a time, and have done most of the work on the father's face.

My process is somewhat similar to how I work in oil in that I create an "underpainting" as the foundation for my drawing, but very different in how slowly I build color, and also because my initial drawing and underpainting must be more refined in colored pencil. In both, I tend to work very quickly throughout the entire process. I think people would be surprised to see me work - I don't slowly move the pencil or paintbrush carefully rendering details, but rather move quickly and intuitively, trying not to worry too much about details until the very end. The "mistakes" I make are corrected with each subsequent layer, and the overall artwork ends up looking realistic.