I saw this when I decided to use quest calculator. In yours RoD guide there are shown wrong requirements: http://www.tip.it/runescape/quests/view/134-recipe-for-disaster

 

While it has a lot higher and a lot more requirements: http://runescape.wikia.com/wiki/Recipe_for_Disaster

 

Because of that sometimes quest calculator isn't accurate.

They aren't wrong.

 

If you look at the calculator there are several lines

 

Recipe for Diaster - requiring only 10 cooking - is the container of the 8 sub quests that you complete sperately

Right below this is Recipe for Diaster: Subquest x - Blah

 

Where 0-9 are listed showing the reqs for each subquest seperately since you can do them seperately

But WGS quest requires whole recipe for disaster quest and it has taken into requirements only that level 10 of cooking.

But the calc doesn't read stats from other quests - that is why the quest required box is seperate.

 

I unticked WGS and 1 part of RoD and ran the calc WGS shows Red because RoD isn't done, but shows the skills in green because I have "270 QP, 65 Defence, 75 Magic, 65 Herblore, 60 Thieving, 65 Farming, 55 Hunter, 23 Summoning"

 

 

What exactly is 'wrong' there? It shows I have the required stats for WGS, which I do, but not required quests because not all of RoD is ticked.

I think I see the issue - according to the calculator you're all set for Recipe for Disaster with 10 Cooking - but in actuality you need a much higher level to "finish" everything. I'm not sure if it can be coded to recurse through subquests and display those requirements in there instead; I'd have to check on it. Thanks for pointing it out :).