If I understand what you're saying, then Ghost Armor would only require a clvl of 5 and the Dusk Shroud would require a clvl of 12.
No, you left out the base level of the examples. Standard is 0, but the exceptional version is 24, while the elite version is 49. If you started out with Greyform Quilted Armor, and upped it to exceptional, the new level req would be the highest req (the base item of Ghost Armor, or level 24) plus 5, so it would be 29. If you decided to up it all the way to elite, it would then be required level 49+12=61.
It can be a hassle to up something and not know this, which is why I scribbled '+5' next to my exceptional upgrade recipes and '+7' next to my elite upgrade recipes, using a Sharpie. I upped a HoZ once with I pally at level 61 thinking he could use it, and then was sorely miffed that I had to go 7 more levels to use it again. I can laugh about it now...