Yes. I just checked it myself, and that is the case.
EDIT: Actually., I need to correct that, because I misread your last post.
Saving the project after lowering the PPQ resolution will not alter the stored resolution. If you restore it to 960 after re-opening, you will see the higher reoslution values come back. But
exporting to MIDI will generate a MIDI file with the lower resolution, and the original resolution will be permanently lost.
I would have corrected sooner, but my internet service went down moments after posted.