Ummm i tried the "X/Y +/- 1" style with different FPS and it worked just fine.
Edit:Ok now i get what you want... have to research more at this.
Edit2:
[quote:1fx2gnjd] Drawbacks
This system can cause problems very low framerates. A game running at 5 FPS means a fast-moving object going at 500 pixels per second will be jumping 100 pixels every tick. This can cause problems with collision detection: if the object is small, it is possible it will "step" over an obstacle without registering a collision. Being aware of this can help you design your game to avoid this situation.
* Very thin or small obstacles are more likely to be missed
* If the moving object is large, it is less likely to miss
* Slower moving objects are less likely to miss
* Instant hit bullets with a small enough step will never miss a collision
The Drawbacks of Timedelta.