Those schools that find they have the space in the spring that they do not have in the fall, have taken advantage of this to offer up to some students. My son , a few years ago, was offered two such spots and was not the least bit interested. He really wanted to go to school in the fall and have that full experience. In his case, that preference outweighed his desire to go to either school that gave him the option of spring admit. Both schools were reach schools for him, and had his other options not existed as they did, he might have decided otherwise.