According the career manager brief I read this year Cpl/LS Sup Techs are green which means that it is at an acceptable manning level. Give it time and it will change. We in supply, and all LOG trades for that matter, tend to have a slower turn over rate than most of the other branches.
It may also depend on how resistant you are to certain Geo areas of the country to serve in. Meaning if you want in badly enough I would suggest you take whatever posting they offer you.