Is it frowned upon to have a short segment of a song, perhaps only one measure, to be in a different time signature? Does the level of frownage vary by style?
Background: I'm working on a classical piece for guitar, recorder and cello. It is in common time, but I needed to slip in a 6/4 measure for the melody I wanted. I am unable to be more specific on the style of the piece I'm working on, as I'm just starting out learning to compose and am spending some time writing and some time reading each day.