A dynamic mark is horizontally centered on its own note's x position, not left/right-justified against it

A dynamic letter's horizontal center aligns with the notehead it belongs to, so the mark reads unambiguously as attached to that specific note rather than the one before or after it.

A dynamic mark's left edge (rather than its center) aligns with the note's x, making it read as belonging to the FOLLOWING note in a dense passage.

Gould, Behind Bars, ch. 'Dynamics'; general convention matched by every engraving program's default dynamic placement.

This rule is about where marks land on the page, so it can only be judged after engraving. Collision and spacing faults live here.