3rd person gives people extra reach when attacking mobs or players

I was playing PvP with my friend in a local server (not the external ones). I was using 3rd person to PvP and he found that I could hit beyond the default hit radius as I'm using 3rd person. (I was using the back view)

What I expected to happen was...:
It could be a fair fight because I thought 3rd person has the same hit radius as 1st person.

What actually happen was...:
I could hit beyond the hit radius (Normal: 2.5: 3rd person: 4.5)

Steps to reproduce:
1. Spawn a mob/get a player in your singleplayer world. (Use survival mode)
2. Hit the mob/player and you can observe that you can hit beyond 2.5 blocks.

Remarks: I'm not sure if this goes for destroy range and front view of 3rd person. This also works for other devices like Android.