Microsoft Project Problem with nested IIF statements

I am using Microsoft Project Standard 2019. I have a calculated column with a series of nested IIf statements and unless criteria 2 or 3 is met, the field displays "#ERROR".

I believe this is to do with the date field showing "NA" when blank. I have tried re-arranging this formula multiple times, using "" instead of "NA" etc, but I can't seem to figure out where I am going wrong.

Requirements:

1. If the Date1 field is blank or NA; I want the calculated field to display "None".
2. If Date1 has a something other than blank or NA AND Text10 contains "Task Created" as the first 12 characters; I want the field to display "New".
3. If Date1 has a something other than blank or NA AND Text10 is not "Task Created" AND Date1 <> Date3 OR Date2 <> Date4; I want the field to display "Change"

I have also tried googling but have not been successful in finding an answer to my problem. Your expert help would be greatly appreciated.

Here is what I have:

Code

IIf([Date1]<>"NA",IIf(Left([Text10],12)="Task Created","New",IIf([Date1]<>[Date3] Or [Date2]<>[Date4],"Change","None")),"None")