Video scaling worse in FCP5.1 than in Quicktime 7 ?!

Question

i have some footage shot on the Phantom 5.1 camera. it is at a custom resolution: 768x1024 (portrait format) / square pixel aspect ratio / 25fps / Photo-JPEG compressor / not interlaced
i'm trying to downscale it to PAL to make a standard definition dvd.
so i make a new PAL (DV compressor) sequence in FCP 5.1.4, drag the high resolution Phantom clip to the sequence, FCP automatically pics the correct scale factor (~56% as i remember), hit File > Export > Quicktime Movie... and export the sequence to a file. Setting: Current Setting, Include A+V, Do Not recompress all frames, Do make self contained.
the resulting movie when played back in quicktime player looks very bad quality. it appears to be approximately half the vertical resolution. i understand about interlacing (i think!): i always playback interlaced clips with 'High Quality' ticked so i am seeing both fields. so i am confident that is not the issue.
this is frustrating, but the problem gets a bit more strange:
if i open the 768x1024 file in the QuicktimePlayer and export it as a Quicktime Movie asking the file to scaled down to PAL at this stage by the quicktime player. the file that quicktime exports when compared side by side with the file that FCP exported is noticably better quality! in fact, is sharp as you would expect.
unfortunately, there is a flaw to this approach also, scaling in quicktime player has no concept of converting pixel aspect so my scaled down clip is a little bit too wide. you can see this in the screen shots, the QT version is vertically sharp but horizontally a bit less sharp.
this is not a problem with checking things on the computer screen, i have gone through outputting these to dvd and checking them on various playback machines. the results are the same. as an aside: I have seen this symptom before when scaling down Pal DV footage within a Pal DV sequence (to achieve split screen and picture in picture type effects), i've always assumed it was a problem with scaling interlaced footage and never looked into it.
can somebody explain why the quality is unacceptably bad when the video is scaled down in FCP and much better (albeit with other problems) when the video is scaled down the same amount in the Quicktime Player ?
i maybe jumping to conclusions here: this appears to tell me is that there is a significant problem with the image scaling engine in FinalCutPro. there is a unnecessarily large loss of quality whenever changing the scale of a clip in a sequence.
i have prepared some example screenshots. this is not from the original footage, rather a clip made from a still image. i've gone through identical steps with it and had the same result.
the original footage, 768x1024 square pixels, Photo-JPEG codec:
http://www.alexkent.net/FCP5scaling/nativeres.png
the comparison scaled clips:
http://www.alexkent.net/fcp5scaling/downscaledbyFinalCutPro.png
http://www.alexkent.net/fcp5scaling/downscaledbyQuickTime.png
Message was edited by: Alex Kent (for clarity)

Answer 1

looking again i don't think my example images are much good, i'll make some more later to try to make the problem more clear.
the FCP one is narrower because of the Pixel Aspect ratio of PAL. the FCP video is 720x576 but at PAL pixel aspect (1.07) and the QT is 768x576 with square pixel aspect. so they're both right in that sense, but the quicktime player doesn't display the FCP one correctly.
resolution: i didn't meant about 50% sharpness of the high resolution original, i meant approx 50% sharpness of a regular standard def PAL image. that is my problem, scaling down in FCP seems to make much worse images than the quality i am scaling down to.
the camera? it's pretty wild. made by vision research:
http://www.visionresearch.com/index.cfm?sector=htm/files&page=camera51new
as i said i'll make up some more explanatory sample images later today as i think this scaling quality is a problem i have run into many times, but never figured out.
thanks.