Hi,
The underlying principle of the Schengen visa is that you only need one visa for the whole
Schengen zone. To answer your question, let me remind about some general rules. If you are visiting only one Schengen country, you apply at the embassy of that country. In case you plan on visiting several Schengen countries, you apply for Schengen visa at the embassy of the country which is your main destination. That would be Austria in your case because you spend the most time there. In situations where you intend to visit several Schengen countries and you do not have a main destination (for example if you are going to spend an equal number of nights in multiple Schengen countries), you apply at the embassy of the country which is your first port of entry.
This is probably the rule that your friends are confusing. If you do not have main destination, you apply at the first-port-of-entry country. However, once you have the Schengen visa, you can enter the Schengen zone through any Schengen country.
Cheers.