When we are working through internal alignment of a unit, alpha-numeric coding helps us to organize and recognize the relationship between content (what) and skills (student actions). Here we have a loose alignment between content and skills - there's not a 1-to-1 match between each bullet on the content list, and every item on the skills list.
The unit plan will focus exclusively on the why, the what, the actions and the evidence. The lesson plan however, is where we focus on instructional techniques - exactly how the curriculum will be delivered.