These vital records lists can be found in the local German newspapers going back to 1872 for births and deaths, but even earlier for marriages. What these lists reflect is only what was _recorded_ for the day that the newspaper collected the information, sometimes multiple days worth. The information changes in different eras, and for one period, the marriage information is identified as marriage licenses, not registrations.
For researchers, the problem has always been when was the birth, death or marriage reported and then recorded? There are examples of families reporting early births retroactively (my Oppermann ancestor reported his daughter's births in Manitowoc Co. in the 1860s, in 1872 - these are found in the state registry). That's why "recording date" is important to take note of for any early vital record. One index in the area found a snafu that was created when recording date was confused with birth date 8-o
Much later on, late birth registrations are collected separately as "Delayed Birth Records" and most of that collection comes from those records reconstructed for Social Security registration: 2 of my grandparents used insurance policies, baptism records and family depositions/affidavits to report their own births from 1888 and 1893.
The newspapers weren't producing original reporting in these vital records lists. But it's possible that a birth, marriage or death that didn't make it into the local Register of Deeds OR state offices may be found in a random entry found in newspapers ;-)
"Milwaukee's German Newspapers; an index of death notices and related items" (1844-1950).
Gary Rebholz, originator/compiler/editor, Milwaukee Wis.firstname.lastname@example.org
Indexing Milwaukee's German newspapers continuously since 2007... helping family researchers find their ancestors among Milwaukee's 99%.