Hi Vince. The answer is you can do this, but you probably don't want to. I think it would mean developing a mathematical transfer function to scale your C data, plot the scaled data, then label the yticks on the colorbar, which will be scaled, but use labels that indicate the unscaled values.
For a simple example, here's what I mean, but simply scaling by a factor of two:
Z = peaks;
Z2 = 2*Z;
cb = colorbar;
set(cb,'ytick',[-12 0 12]','yticklabel',[-6 0 6]')
That works, but it's overly complicated even for a simple scaling without moving the central value around. What you are proposing seems more complicated, more prone to error, and less intuitive for the viewer to understand. In general, if you ever find yourself wanting to do such funny things with the colorbar, or if you find yourself inventing complicated colormaps to show what you want to show, it's probably a good time to step back and rethink what you're doing.