Can someone explain to me why a low Gh/S have the same price reward and more than me and I'm 10x faster than him


102.79 GH/s   16.57 GH/s (16.12%)   294719.300 (19.31 G)   3h 25m 15s   2.46844188 XJO


978.22 GH/s   40.97 GH/s (4.19%)   294719.300 (19.31 G)   0h 21m 34s   3.49648346 XJO        <------ ME


Previous few block this guy got 4 XJO and me only 2.5  this is so weird .. and I was mining from the last 18 hours

HIM     2724984   2017-07-21 10:05:59   + 4.11515107 XJO
ME     2724984     2017-07-21 10:05:59   + 2.39061241 XJO


HIM 2724932   2017-07-21 09:30:50   + 4.16096638 XJO
ME 2724932   2017-07-21 09:30:50   + 2.36985016 XJO


HIM   2724846   2017-07-21 08:34:00   + 5.21987548 XJO
Me    2724846   2017-07-21 08:34:00   + 1.10739593 XJO