H264 Main Profile frame rate issues

Hello all

I am encoding using the latest FMLE from a Niagara 6116 (osprey) SDI input (PAL)

544kbps video, 56kbps audio, Main profile, level 3.0, input 640x360, encoding to 480x270, CPU Never topping more than 55% but the output from Main Profile looks like the frame rate is about 15fps, the encoder reports a steady 25, the input is 25. If I change to baseline then it looks fine.

I would like to use the main profile to get as much quality out of this as possible.

Any ideas? Suggestions?

Thanks