This is correct.
The 6.9" of snow at ORD as of 6PM this evening means today has featured the largest calendar day snowfall since 7.0" fell on Nov 21st, 2015.
ORD is beyond that 6.9" total now for today, which means whatever the final snowfall total is today, today will feature the greatest calendar day snowfall since 16.2" on Feb 1st, 2015 (GHD2).