I've taken systems down for maintenance/changes and brought them up after a delay, and my reward for that block ended up being essential unchanged compared to if I'd mined constantly. Statistically it works out to the same in the end.
Did the same many times, people hate the maths and are rewarding 'Bragging rights' for a statistically 99% guaranteed prediction. There is still 1% chance the block is found during your maintenance, but if you do your homework you may choose the best time for the maintenance.
Yes, it is similar to pool hoping and instead of maintenance you can switch pools for a while, then come back and loose nothing.
Similar situation when bringing a new miner online.
The new unit was running for about 30 mins and scored about 90% of the value for the entire round compared to the existing miners.