Yes, you're correct, and it is MY belief 99% of Americans, when they SEE that word, subconsciously says EYE SAY AH ... or stumbles because they are not bible/church people (who are VERY familiar with the printed word AND the pronunciation of; EYE SAY AH.
The added "S" on the word occurs once (that I can remember" in the KJV NT ,,, but I can't remember where, nor will my search engine take ne there