Paul,
Those females can lock 30 times, but if they are not ready to cycle, or start growing follicles, they just won't do it until they feel conditions are worhty of them putting all that effort into creating babies. This is the part that makes this more of an artform than a science. I wish I could be more helpful, but don't forget that your snake is a woman (and we all know that they do what they want, when they want).