Residential and commercial roofing are distinct, because each of these two specializations has its own particularities. They are related to the shape of the roofs: the residential ones are, in most cases, pitched, while the commercial roofs tend to be flat. There are also flat roofed houses, just as there are commercial spaces in buildings with sloped roofs, but these are exceptions.
The roofers in San Antonio in residential roofs have experience in working with tiles and shingles, with gutters and downspouts, with chimneys, attics and so on. On the other hand, specialists in commercial roofs are used to working with waterproof membranes, parapet scuppers, etc.
In general, roofing companies get specialized either in residential roofing or in commercial roofing. Not in both, because specialization in a certain field ensures the ability to solve better and more efficiently the problems related to that field, due to accumulating experience only in that direction.
There are also large roofing companies that have resources to handle both roofing options, but these typically have separate teams that each handles a type of roofing.
When hiring a roofing company for a project, make sure that it specializes in your type of roofing, and its portfolio is full of projects similar to yours.