Negative. I have nearly 800 shroud completions on all my toons combined, I guarantee you there is no difference in the drop rate of the ingredients, yes it does seem like bones drop all the time and scales don't but its simply not true
this time you got 13 bones and 5 scales, next 20 shrouds you will get 10 scales and 3 bones and so on... Prices for them are so easily explained too, any single aspect recipe requires at least 2 scales, 2/3 of them require 3 scales, any double aspect recipe requires 5 scales, some of them 6 scales, same numbers for bones are 0 and 1 for single aspect, and 1 and 2 for double respectively
so everyone has shortage of scales and surplus of bones, which leads to prices of them on AH and trade chat. Anyway the point of this was to buy a scroll, not argue about drop rates and it seems I can't do first and got too much of second so if there is way for someone to remove this thread completely, would be appreciated if you do so, thanks.