Mountain species require very LITTLE additional vitamins or calcium in addition to a quality diet. I feed ONE cricket every 2 weeks, lightly dusted with a multivitamin to each Cham in my collection. Since mountain chameleons have a relatively slow metabolism compared to a veiled or panther any excess supplementation will create health issues which ultimately reduces the quality and length of life. The margin error is very small when it comes to supplementation and most of what is said on this subject here way overstates the need for it.
When using supplementation, less is more.