If u retire u lose 8.7 million exp and u will get a 30 Exp bonus per tick
8,7 million / 30 = 290.000 ticks (after this u have gain the amount of exp u lose at the retirement)
290.000 ticks / 5 =  58.000 ticks with x5 
58.000 ticks with x5  / 60 = 966,666 hours
290.000 ticks = 290 million regular exp + 8.7 bonus exp = 298 million exp
For example 
Round one:
Player 1: gain 8.700 ticks * 1.000 exp = 8.7 million -> retire
Player 2: gain 8.700 ticks * 1.000 exp = 8.7 million 
Round two:
Player 1: gain 8.446 ticks * 1.030 exp   = 8.7 million  
Player 2: gain 8.446 ticks * 1.000 exp + 8.7 million = 17.146 million
Round 3:
Player 1: gain 8.446 ticks * 1.030 exp + 8.7 million  = 17.4 million  
Player 2: gain 8.446 ticks * 1.000 exp + 17.146 million = 25.592 million
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Round X:
Player 1: gain 290.000 ticks * 1.030 exp  = 298.700.000 million
Player 2: gain 290.000 ticks * 1.000 exp + 8.7 million = 298.700.000 million
If u retire more often for example 2 times u get the double exp bonus but player two has round about the double exp advance.