In the past I've put a few Lapis on hammers and worked it up to 450 and fortune/looting III. This time I made a hammer and had lots of lapis so I dumped all 450 in. I got fortune III, but no looting. I even went on a slaughter spree and no looting has shown up. Is a hammer *only* able to work up looting if you start low on lapis and work up?