This company does not value its Installers. You be hired in as a Full tme employee and be told you are a "at will" employee. This means you are basically a temp but you can and will be let go "at will" of management, You will only work if they don't run out of work,
This is a company that is not afraid to terminate you at any time, you are just a temp in their eyes even though you are hired in.
This is a very unfair employment situation in that you will be released at any time for any reason even if you are doing well. They do not value the installation crews and will not invest in your success.