Lower Saxony announced yesterday that the necessary state election (because of the swing vote now going from the Greens to the CDU).....will not be on the same day as the German national election (24 Sep)....instead, it'll be 15 October.
The basic reason is given that the parties need time to prepare for the election. If you remember the original story....the normal election would have been in late January of 2018. So, in some ways, it's necessary to put some extra time into this.
The CDU folks (Merkel's crowd) were hoping that it'd be on the same day as the national election and get some extra votes.
Does it really matter? The maximum number of residents showing up to vote....would have occurred on the 24 September national election day. I would take a guess that you can trim 10-percent off that number with the state election.
The one disadvantage for the CDU? Their guy isn't that well known, and he'll need the extra time to introduce himself around the state.
The one disadvantage for the SPD? There's been some emails that suggest that they (the SPD) worked to lessen criticism of Volkswagen back when the big scandal with diesel hit.