I need to verify some of this as there is potential background genes coming from the Brown Leghorns is affecting some of the results... but: Melanotic turns the entire feather black. Note that this is not a partial flip, the entire feather vane turns a charcoal black color. I'm looking at birds in my yard right now that are almost entirely black except the faint striping from Columbian. Columbian opens up the rachis with a flipped color, in my birds, this is white because I have selected heavily against the gold gene. Pattern pushes the flipped color to the outside of the feather. Combining these genes with mahogany pushes the fill color to red. From this perspective, mahogany red displaces white which displaces black. Think about it a bit more. We may both be wrong in describing how patterning works. I can see counterexamples in my own birds as I write this.
Should mention that I describe Mahogany as Red because it is the closest to red that I've seen in my birds. The other forms of red I've seen are actually reddish brown unless they are combined with Mahogany. One caution, I have partial color blindness in the red/brown color range. I can see them, but they kind of run together. I may describe a color as brown but you might see it as a shade of red.
This brings up another question I have not looked into. Can lacing be produced with color combinations other than black/white (Silver Laced), gold/white (Golden Laced), red/white (red laced), and brown/white (brown laced)? I haven't looked into this, but suspect there is a variant similar to Golden Buff that could be produced on a laced feather. I saw this in a few F2 birds about 5 years ago but did not pursue it as it was not in the color range I am selecting.