That seems about right... Trophy in Deponia

Missable!

On the Platform area above the Post Office are several pigeons. In the Mayor's Office you'll find a magnetic field device that can be used to control them.

Imagine this thing like a telephone keypad: 1-3 on the top row, 4-6 in the second row, 7-9 on the third, and a lonely 0 at the bottom. Sequence: 6 / 5 / 5 / 4 / 5 / 5 / 6 / 5 / 5 / 8. Back out of the puzzle to unlock the trophy.

If you skip this puzzle, you will void the trophy, and must play through the game again to unlock it.