Let's be clear about CE convertible seats here.

In economy config they are 3x3, with 17in width and 34in pitch.

In CE mode the ABC seats contract so that there are two seats A and C which each have 34in pitch and 19in width.

In CE mode the DEF seats widen out so that they also have 34in pitch and 19in width.

The advantage of sitting on the A-C side is that the contraction of the "B" seat creates a wider armrest which maes it better to sit on the A-C side.

Apart from the wider arm rest between A and C the seat width (19in) and pitch (34in) in CE should be the same.