If you’re the birthday boy, and you’re Mozart, well, the party should be at least a little decorous. But the occasion also demands wit, as well as a dash of charm, perhaps, to season things just so.

All those qualities (and chocolates, too) marked the festivities Saturday evening at the Michigan Theater, where the Ann Arbor Symphony Orchestra celebrated Mozart’s 256th birthday at its annual Mozart Birthday Bash.

Other configurations of Mozart works would, of course, show a difference face of this 18th century master, but it was beguiling grace that won out Saturday evening in a program that featured the Divertimento No. 11 in D Major (a birthday present from the birthday boy to his sister, Nannerl); the last piano concerto, No. 27 in B-flat Major, with Ran Dank as soloist; and the “Prague” Symphony, No. 38 in D Major.

Music Director Arie Lipsky, at the podium for the entire program, has a long acquaintance with the Divertimento and happy memories of playing it, as a cellist, on one of his first professional gigs as a teen-ager in Israel. The fondness showed, in a polished, cleanly shaped, intimate reading filled with light and humor. Oboist Timothy Michling was the piece’s leading man, and his playing was more than handsome. At first the orchestra finishes all his sentences—a trick Lipsky brought out nicely in the opening Allegro molto. By the end, Michling has the limelight to himself, in delicious dance tunes that provide lilt and loft to the concluding rondo.

The Divertimento is chamber music; the piano concerto that followed, with the 29-year-old Dank at the keyboard, seemed as much so, in its own way. Dank, a rising player who is a winner of the Young Concert Artists International Auditions (among many other competitions), brought an intimacy and a pearly sound to the work. Still, he made the most of its bigger moments. Once or twice in the sunlight-filled finale, he surprised with an uncharacteristically strident tone in his fortes, but grace was his calling card overall. The orchestra, after a start in which the brass seemed somewhat under pitch, was a fine partner.

Some years, the A2SO has presented Mozart operas in concert at the Birthday Bash. The operatic components weren’t absent this year; they were just contained within the melodic material of the concerto and the concluding work, the “Prague” Symphony.

Even if Mozart had not borrowed from “Marriage of Figaro” in the “Prague” (stealing from the best—always a good policy), it would not be amiss to hear in the work operatic elements. Lipsky clearly does, and he brought out a fine sense of dialog among characters in the opening Adagio and Allegro.

The orchestra was very on its game in the middle movement, responding to Lipsky’s finely modeled dynamic ideas with beautifully graduated playing. The phrasing was exquisite here, with suspension points that kept the music unfurling over midpoint after midpoint.

For excitement and adventure, though, the finale was where it was at. That’s, of course, what Mozart must have had in mind. It was certainly what the A2SO delivered.