Hey guys!
I'm very confused/frustrated because any website/institution gave me a proper answer to me and my wife's case. I kept it very short and didn't mention all the annoying details that came up within the last months

The main question: Does the counting of an old 90/180 Schengen C (one year, multiple entry) visa reset, after an embassy issued a new visa (89days single entry) for an upcoming family-visit?
Situation:
My wife had a visa (starting from march 2016 - march 2017) and used about 88 days of it (with multiple entries). The last time she left the Schengen-zone was the 15th August. Because we married in summer, she needed to get a new passport due name change and therefore a new visa that the embassy succesfully issued (after she was again back in her country of course). It's now one week before the departure and we panic now because we red on the internet so much crazy stuff about this 90/180 days Schengenrule-calculation etc.. The calculator says, that a next visit would be possible in November, whereas our planned trip starts at the beginning of October. So either, the embassy made maybe a mistake in ignoring the 90/180 clock or this clock got reset due the new passport/visa.
Answers:
Embassy: The consultment with the embassy was a bit weird, coz they told us the rules like they have been before 2013 (90 days stay in every 180 days period after the very first Schengen-entry) and because she didn't use all days of the old visa - That she could easily come in the middle of September again (-180days = middle of march).
Ministry of foreign affairs: Talk with the ministry of internal affairs, we don't know.
Ministry of internal affairs: People didn't know and forwarded us to one person that was never there..
Foreign Police: A valid visa is not a reason to a succesful entry.
Conclusion:
I red on the internet a lot of different opinions. That every country "interpretes" this EU rule/law individually (!?). That there would be a reset. That there would be no reset. That it's impossible to bypass the clock, because otherwise all people would be able in issueing more visas in order to stay more than 90 days. That it shouldn't be a problem at all if the embassy grants a new visa. That in some countries deal with it still like with the old rule before 2013. etc.etc.etc.etc. Also on the websites of the ministries etc., they didn't mention the rule to count 180 days back depending on the planned entry etc.. On the other hand, a Schengen country is a Schengen country. So I'm very confused now and we're afraid that there could be serious consequences if my wife enters/leaves the Schengen zone and suddenly gets blamed to come illegaly, because she ignored the 90/180 rule, even though the embassy issued her a new visa (which should deactivate the old visa and theoretically reset the old clock).
So, maybe you guys know some better information than me. It all comes back to the question if a new visa resets the clock. But nobody could answer me this question yet and on the internet I find so many different answers or in other terms misinformation, that I can't rely on these "theories".
Sources:
Not possible to mention links here - coz it's my first post. PM if you're interested.
Thank you for reading this information. And I hope that the answers of this post, will help people in the future, so they also wouldn't go crazy because of this annoying and confusing rule that came in 2013. I will promise to keep you uptodate if something worked out or not, regarding the upcoming trip. Maybe I also just didn't find approbiate information, that confirms the theory if a new visa will reset the clock of an old one, or not. I called it theory, cause many people/articles say so many different things.
Thank you very much for reading this (and also sorry if I took your time),
Ricola Tesla