In answer to a previous question asking about DLPs:
DLP, SXRD, D-ILA, and RP-LCD:
Rear projection technologies generally cannot do "dot for dot". They typically don't use software overscanning, but the image they throw is typically 2-5% larger than the boundaries of the glass frame it hits. So they DO "dot for dot" but those dots are hidden behind the edges of the frame.
Note: this limitation does not exist with front projectors, only RPTV sets.