If you only go by the 8 mendatory poses it's like 50/50, but if you add how they look relaxed, how they look when they move, you clearly see the difference in term of muscle bellie bteween Kai and Phil and that's why Phil took the advantage IMO.
+ The fact he was the current champ to beat, which mean you must be 1% better than him to take the trophy otherwise he keeps it.