Date of final -os to -us

On pg. 140 I write "An o in a final syllable before final -d, -s, -m, or -nt became u already by the middle of the third century BCE" following the traditional dating of this change, but Kanehiro Nishimura in his 2008 UCLA Ph.D. dissertation, Vowel Reduction and Deletion in Italic: The Effects of Stress, calls attention to the form L[ECIO]NIBVS (ILLRP 7) in the Caso Cantovius inscription from near the Fucine Lake which dates to the end of the 4th century.  This suggest that the date of the change of o to u at least before -s has to be pushed back at least 50 years or so. Similarly on pg. 192 in the list of the absolute chronology of sound changes change 

"10. -oC > -uC (3rd century BCE)" to "10. -oC > -uC (ca. 300 BCE)."