See posts #596 and #600 of the One Rincon Hill construction thread:
http://forum.skyscraperpage.com/showthread.php?t=107919&page=30
One Rincon does not look any taller than 345 California Street in elevation.
Could it be that all these different height claims are all correct, but it just depends where one measures the height from - Level 1, Level 6, Roof, or top of structure? Without any further speculation, could someone please post the PDF's of the drawings here and in the One Rincon Hill construction tread?