While the fact that these changes were made is factual, the reason why needs clarification.
As I make the following statements, I hope the readers (including Joe), are willing to hear me out to the end.
The KJV of 1611 was not without PRINTING errors. Now then, even though there are approximately 400 textual changes made away from the original 1611 Edition, they were not made to change a text that was believed to be correct in 1611, and then found to be in need of correction later: rather; there were “textual” changes made from the 1611 Edition because it was found to be a PRINTING error, (an error that was made in the typesetting in the printing of the 1611), was not discovered until AFTER the printing was complete.
One of the tactics used by, and taught by textual critics to say the KJV is not perfect, is the fact that there are in fact differences between the 1611 and the 1769 we use today. What is not often discussed, is why these differences exist. I do a lot of writing. I write Bible lessons, articles, and other writs. However, I have never printed anything that I have not had to go back and edit my own work. I find typos of all sorts, (even though I have spell check, and normally spell words relatively well). Sometimes I find that my typos are because my brain is moving at a different rate of speed than my fingers. I may think five words, but only type four (or visa-versa).
Hence, to keep this concise, the printers had to set the entire Bible from a handwritten manuscript, one letter at a time, on one page at a time. During this process, many setting mistakes were made. Words were missed, miss-spelled, and so forth. Additionally, between 1611 and 1769 the spelling of the English language was still being standardized, and the font was changed from a gothic type, to a roman type.
Additionally, as has been noted, there were also differences between the Oxford and Cambridge Editions. Much work has gone into research to determine the correct rendering of the text.
Jack
I actually had to edit this, I forgot the words, "of speed", (relating to my typing).