blacksmithing plans question for stratholmeFollow

If this works like it does in Blackrock Depths, then the plans disapear if the skill level is above you, I had plans disapear on me at skill level 283 or so (luckily there werent any other bs's in that run)
I've heard someone mention it had to be at least 285 but I suspect you just have to be even level with the plan or higher, Should always have the highest blacksmith look at the plans to see what they are imo.