According to the Wiki, Hit Points increase according to the following formula:
HP = 80 + (End x 5) + (Level -1) x (2.5 + End/2)
End Hit Point Gain/Level
1 3
2 3.5
3 4
4 4.5
...
10 7.5
So my question is, do your Hit Points round up if your End is an even number?