Yes you are right!
I feed all my Eclectus the Pretty Bird Eclectus pellets (all three breeding pairs- R.S.- S.I. and Grand) I even have a diet plan when weaning that brings them over from my hand feeding formula to the pellets. They do not contain the color additives (only natural colors from natural occurring ingredients) that make up the process. I work with Dr. Michael from Pretty Bird who is the chief Ornithologist at Pretty Bird (presently in Costa Rica at a wild bird feeding station)
The trouble with Eclectus and their unusual feathering is only when "Yellow Stripes" appear on their belly, between the legs. This is an indication of liver fatigue. What I think with Orange feathers is that you have a mixed Eclectus. You see Eclectus have seven species all together and many breeders don't take the time to weed out the different species prior to breeding. I've been breeding Eclectus for over 15 yrs and in the last 5 years when traveling to shows and expo's looking at the offerings there I've failed to find only a handful of what I consider "pure-bred" Eclectus.
There is nothing wrong with your bird. Eclectus feathers that show orange can be several different species of the Dominate. And yes I do augment all my birds with a Lori-Nectar in addition to their water bottle to boost the fruit intake of the species and found that to be very healthy for my birds. They are really nothing but a big Lori anyway, as noted in the wild.
Here are some very good reads, especially the new 10 study I think you will find fascinating, this is not the whole report, for that you'll have to find the issue and buy it. But it is worth the effort and will help with your understanding of the species. Especially the colors and patterns of the Eclectus.
http://www.birdchannel.com/search.aspx?q=Eclectus <-general Eclectus information
http://www.birdchannel.com/bird-magazines/bird-talk/2009-february/bird-talk-eclectus-colors.aspx<- special issue on a 10 yr study in the "islands" of the Eclectus (all) species
P.S.- my feeling is that you have a cross Vos-S.I. which is very common.