Honorifics are cultural.
In undergraduate -- It was always Professor LastName. In grad school, other cost, it was Doctor Lastname. We had a discussion there, and learned that in Germany, it was Herr Doctor Professor Lastname.
In undergraduate -- It was always Professor LastName. In grad school, other cost, it was Doctor Lastname. We had a discussion there, and learned that in Germany, it was Herr Doctor Professor Lastname.
When talking to them, it's Herr Professor.
Austria loves their honorifics, though. Every school teacher is a Professor, and the Professor's wife is Mrs. Professor.
Since the difference between tenured and non-tenured teachers is beyond the understanding of 10-18 year old pupils, they called every teacher "Professor".
Same in Poland! But only for high school.