is there an issue with Skulls in 'Advisors/?definitions=true' ?

Hello everyone i am using the API with php anyway when i reed the JSON output i noticed that everything is connected with hash numbers so if i search for Nightfall and look at the modifiers i won't find like ( Epic, Airburn,Trickle ... etc) but it will be like (1,3,14,17... etc ) so these numbers must have meaning , ======================= so when you look at Scripted Skulls, you won't find the same numbers, there are some missing numbers ! or i understand it wrong . first here is the call ( Advisors/?definitions=true ). ======================= anyway lets take this weak data as example this is the Nightfall hash : 1749151224 (Response.data.nightfallActivityHash) and this is the details : (Response.definitions.activities.1749151224 http://pastebin.com/taQ0sxyN ======================= so Skullindexes is : [spoiler]skullIndexes: [ 0, 13, 15, 16, 17 ][/spoiler] ======================= and if you go down you will find scriptedSkulls (Response.definitions.scriptedSkulls) http://pastebin.com/ysPxUV5i ======================= anyway i made a function in php that get nightfall skulls and compare it with scriptedSkulls ======================= but that what i get : http://pastebin.com/z9Rrz5UR ======================= so there are 15,16and 17 not defined in scriptedSkulls sorry for that stupid question