Help me get my head around conforming framerates

I shot my footage at 50fps and am doing my edit in a 25p sequence. I can easily conform my footage through the automatic speed command and get a perfectly smooth slow motion, but the problem is that I want this slo motion effect to be just slightly noticeable (just slightly slower than normal speed). So, if I just perform a speed change (speed up the clip) it seems to me that I don't get the smooth motion result but some kind of frame blending, skipping is happening on the software side. Am I thinking something mathematically wrong when I expect to just, for example, interpret the footage (in Adobe terms) as for example 35fps and the software would automatically compensate clip length so it can play all the recorded frames but without any frame blending whatsoever. Of course, if I want to go slower than 50% than fcpx obviously should do some magic to compensate for the missing frames that wasn't in the recording in the first place.

Hope you guys can understand and help with what's bothering me.

Thanks a lot

You have choices.

Why are you conforming then speeding up? Have you tried just dropping the clip on the 25fps timeline and then selecting custom speed and entering your desired value? (Say 80% for example) that should help, I think.