I think the most correct way to put it is that srpsohrvatski or whatever you want to call it is a pluricentric language with a few mutually intelligible standards the same way German is.
Austrian High German is different from German High German is different from Swiss High German.
For example, Austrians refer to bread rolls as "Semmeln", while Germans call them "Brötchen". Austrians tend to avoid the Preterite in spoken language, while Germans use it pretty frequently etc etc.
"Ich holte mir eine Tüte Brötchen" vs "Ich habe mir ein Sackerl Semmeln geholt", for a practical example.
And now you're making the fallacy of differentiating by the German-Austrian border and not the Danube.
Source: Am Bavarian, we're officially nearly a fourth of Germany and the Austrians talk like we do ;)
More seriously, I couldn't tell you if anything about tenses is written (and differently) in Austrian school books, or if it's just the dialect creeping up.
What I can tell you that your example sounds kinda made up, although of course I know it's proper German.
Sorry, but I prefer to stay with the Yugoslav term - adding more and more letters is just another expression of petty nationalism.
Also, the M in BCMS is Montenegrin, the latest made-up language, not Macedonian (which is separate). Seems like not even the defenders of linguistic seperatism can keep up with the insanity ;-)
I wrote BCMS in my original post because it saves me the most trouble. If I say "Serbo-Croatian", a lot of people bristle at that. As a foreigner, I can't say "naški". And if I name the specific variety that I learned years ago when I had to buy a textbook, people might accuse me of having political sympathies with that country. (I get a lot of grief from people about this when I am in the region: "as a foreigner, why did you choose to speak with vocabulary typical of that country and not our country?").
You're trying and that is respectable.
People that do "govore po našem" or speak ours can and do often push their version most suited for their aims. Notice there is no "nas" or us in that version.
Austrian High German is different from German High German is different from Swiss High German.
For example, Austrians refer to bread rolls as "Semmeln", while Germans call them "Brötchen". Austrians tend to avoid the Preterite in spoken language, while Germans use it pretty frequently etc etc.
"Ich holte mir eine Tüte Brötchen" vs "Ich habe mir ein Sackerl Semmeln geholt", for a practical example.
And yet we consider it the same language.