OK, I just went to the Smithing Guild and talked to the NPCs, and my ranges were way off. My Smithing skill is 57. The highest recipe that Hugues, the free support NPC, would give me was level 61, meaning a range of 1 to 4. The highest recipe that Wise Owl, the advanced support NPC, gave me was 66 and the lowest was 62, meaning a range of 5 to 9. If this pattern holds true for over 100 (no reason why it shouldn't) hexed gear will cap between 105 and 109. The only cooking recipe that I cannot get at 100.9 is
Himesama Rice Ball, which I would guess is 110 skill. I need to just try to get that last 0.1 to see if it shows up in the advance support NPC listing.