Two thoughts:
1. Keep in mind that the definition of LD has historically required average to above average overall intelligence, which means that the average IQ of children with LD will by definition be higher than that of the general population.
2. There is data to suggest that the further one is from the mean, the more intrapersonal variation there is. (Hence, splinter skills and savantism in the intellectually-disabled population.) This kind of variation in the right-hand tail might look like LD.
