Your question indicates that I misunderstood the Handbook :-)
I understand that in situations in which the new version is not numerically bigger than the old one (as in this case), PORTEPOCH much be increased. I searched the ports tree and found several ports with PORTEPOCHs greater than 1 (archivers/rar, astro/google-earth...) so I bumped it from 1 to 2.