Let's say that for me (and most probably I'm wrong) henka waza is if applying ikkyo and uke straightens his elbow, I make an adjustment to apply ikkyo with his arm straight. As an aside, I don't understand what's wrong with applying ikkyo to a straight elbow. As a henka (for others it may be the kihon) you can apply hiki otoshi to that straightened arm and it still will be ikkyo / ude osae. Even the final pin will be the same. It will just not be the robuse kind of ikkyo.
No you are no necessarily wrong, it is just a matter of vocabulary and where one thinks ikkio stops and where ude or rokkio start.
For me ikkio is an arm lock that involve the arm and the shoulder in a double rotation, Ude a scissor action on the elbow.
Hence I see a change from ikkio to Ude.
Now if you see Ude as version of ikkio then no there is no change.