Provided that this is even true, starch naturally occurs at ~70% amylopectin and ~30% amylose. Lets pretend that they filter out the amylose some how for vitagro, aside from the fact that it is technically no longer starch, all it does is raise the GI and digestibility. I believe a mixture would actually be better since it provides a quick onset, then a slow stream of carbohydrates. In reality though, if there is a difference, I doubt its realistically significant.
If the bio labs were still open (end of semester) and I could get in touch with my old lab instructor, I would do an amylose test on both and find out which has more. Maybe someone who has such resources would like to try it. All you need is yellow iodine and a colorimeter, we did similar experiments in Bio 1101. I would bet the difference would be negligible. Maybe I will see I can do this in the spring.