Yes, it is a confusing issue to say the least! Many of the evang. luth. churches in America became United Churches of Christ (UCC) and then some of them belonged to the Missouri Lutheran Synod. There have been some excellent posts over the years on the Gen-de-l list which provide more specific information about the German-American churches.
Some congregations were more strict or had disagreements and thus, split off. It is interesting that these two religious communities felt their beliefs were similar enough to share and build a church together!
Bob