Hello Oori,
That is because -surf_A specifies the name of the surface as it exists in the spec file. In fact, -surf_A does not have to be fully specified. For example if in the spec file you have a surface called LH_WHITE and one called LH_GRAY , you can just use -surf_A WHITE or -surf_A GRAY to load lh_WHITE and lh_GRAY, respectively. Do not use -surf_A LH_ however because that string does not uniquely identify one surface (you have in this example 2 surfaces that begin with LH_ ).
cheers,
-ziad