I have problems with my Ninjitsu training. I been summoning mirror images for quite awhile and cannot get above 57.5 in the skill. However, if I decide to use Focus attack, the skill will increase. Is the skill gain chart incorrect?

If the minimum skill on Mirror Image is 20 then you shouldn't be casting it past 60. Looks like something wrong with the training guide. - JC the Builder

Alright thanks for the help. I am finding UOGuide to be a very valuable source, even if some things need minor adjustments.