You are absolutely right!

I tested it and IV is not needed. Even went through the dotnet source code and realized IV that I was setting wasn't even used. When this calls this the IV is set to null!
For some reason in my initial tests when I was first implementing this, the code only worked when I set the IV (I wasn't aware ECB mode doesn't use IV). Probably because I was changing more than one thing at a time... silly me...