Is the Preview Window always an accurate representation?

Question

CS3. Two issues:
1.
1920x1080 menu with 1920x1080 motion background(mpeg file). The menu file has an outline as well as drop shadow effect created in Photoshop.
However, in the preview window, the outline and drop shadow look different(see example). I realize I could get rid of the problem by collapsing the effect in Photoshop, but why do I have to? Some kind of scaling issue........?
2.
I have a motion background to the menu. What's moving is a little circular blade to the left of play movie, which spins. It makes 2 complete circles in 20 frames. The 11th and 21 frames would look like the first. ( The reason the background movie is 2 complete spins looping(instead of one) is that Encore won't use any movie less than .4 seconds as a menu background.)
  Anyway, the preview window doesn't show a smooth looping spinning blade. It kind of starts again after 20 frames of looping instead of going on continiously "forever",  which is what I want. OR is this just a preview window problem which will go away at burning time.
Any ideas?

Answer 1

Thanks for the title remote info. I ended up linking it to the main menu. It plays exactly the same.
The Transition Movie DOES play if my burned DVD plays in my laptop computer's internal DVD player. It also plays unburned within the project/within the preview window in Encore.
The very same DVD does NOT play the Transition Movie if I place it in the external "traditional" non-computer DVD that is hooked up to my 32 inch LCD TV set. It skips over the transitional movie and goes right to the regular movie. It's like my TV's DVD player ignores it(the transitional movie).
So my transitional movie DOES play:
1. As part of the project, unburned , and in the Encore preview window.
2. After burned onto disk and on my laptops internal DVD player.
Transition movie does NOT play:
1. After burned and on my regular DVD player hooked up to my television