You have to remember that true Pal is 50 Hz not 60 and NTSC is 60 Hz you are thinking of the frames per seconds in NTSC its 29.97 Pal draws more lines on the screen but slower at 50 times per second then NTSC so whan you play a pal game on a true NTSC Amiga you usualy cut off a small portion of the screen on the bottum and it will run at a different speed because the refresh rate is faster (60 times per second but less lines to draw).
I've read your post through a couple of times and I don't really see what you are trying to say, maybe it is because I'm missing the .'s defining the sentences? I'll try to break it down into pieces...
Yes, I know that 'true' PAL is 50 Hz and not 60 Hz. Yes, I know that PAL 50 Hz draws more lines on the screen but at a lower pace than NTSC. Yes, I do know that running a PAL game on an NTSC Amiga means cutting off a bit of the bottom of the screen. And, in my post I did never state otherwise, rather, I did state exactly the same as in your post.
That leaves us with the FPS. You say that the FPS in NTSC is 29.97? Odd. On my TV running the Amiga and/or other consoles in what often is refered to here as 'NTSC-resolution' (or, to be correct, PAL 60 Hz) means getting an FPS of 60.0. I am pretty confident that the FPS in the US on an NTSC television set isn't half of that. So, what am I not understanding here?