Re-Thinking Magic Item Stocking

In the previous post about cloning the original random magic item tables, I mentioned that there's a 75% chance of getting a +1 item on the swords and armor lists, which I translated to a 12 or less on 3d6. I followed that rule in general, but I broke down the +1 swords into different types. But what if I used a universal table for both swords and armor, based on the armor table?

    3d6   Item Bonus
-------   ----------
 3-12    +1
13-15    +2
16-18    +3

Which means that there would be a follow-up roll of some kind for each category. For example, a +1/+2 result when rolling for armor would have a d20 follow-up roll:

1-9: shield
10-17: armor
18+: both

This would simplify the charts, but require extra rolls. Does it seem worth it?