Q. Is the Alesis Micron Modulation Matrix a system of getting the numeric values to correspond to changes or variations from various sources, or...

A. To put the mod matrix in analog terms, think of the "source" as a control voltage generated by an lfo, env level, mod wheel position, etc. This "control voltage" modifies whatever destination you choose for that particular mod routing. The depth of the modification is determined by the "level" setting for that particular mod routing.

For example, I want m1 to control efx mix. source=m1. destination=efx mix. level=+100%. Now m1 will control efx mix from 100%dry to 100%wet.