Undead Anatomy 4 question

I was working on something with the Undead Anatomy spell and the 4th version has me a little confused. It lists some ability score changes listed as size for tiny and large undead, but those sizes are already covered under UA2. I believe these modifiers are only supposed to be for incorporeal forms, but does not specifically say so. But then why isnt there new ones for small and medium?

So if you used UA4 to change into a corporeal tiny/large undead, would you use the modifiers listed under UA2 or UA4?