There is a reason why bounty campaign is extending, usually it's because the ICO token sale duration extended, that's make bounty campaign also extending. Sometimes the ICO is extending because it's not reach the softcap and the project owner want to extended the duration of ICO until it reach the softcap.
This may seem surprising, but there are projects that extend ICO (and bounty), having substantially more than softcap. For example Ubex.com.
Whatever the reason was, it is not beneficial to bounty hunters.