Stone dust contains particles of many different sizes. The downside to using stone dust is that it may contain too many fine particles. I dont recall the exact gradation, but I think typical stonedust from the landscape store may have up to 20 percent of particles that sift through a #200 screen. Too many fine particles allow the bedding material to retain excess moisture. This may cause frost heaving.
Sand contains less fine particles (I think 5 to 8 percent), therefore retains less moisture, and makes a better bedding material.
So thats the long version of why the paver companies specs sand bedding. If this were a commercial project, like an open shopping mall floor, I'd use the sand, or someday someone would trip over a heaved paver and sue everyone in sight. For a residential patio, I'd use what you have. Good Luck.