The reasons for the page variances is that some have different sized pages and different sized fonts. However, unless it's a different version from King James Version (New King James Version, Amplified Bible, The Message, etc.), they will have the same message and words (not counting 'extras,' like dictionaries, concordances, etc.). So, if you read, say, a 600 page King James Version Bible through one year and a 1,000 page King James Version Bible through the next year, you would be reading the exact same content and the exact same words.