Beginning March 16, 2018, NACHA requires that same-day items are posted by 5 PM local time the same day they are received. 

When the NCUA indicates “by” 5:00 PM, this means ‘anytime’ before 5:00 PM  That means 6:00 PM AT, 5:00 PM ET, 4:00 PM CT, 3:00 PM MT, and 2:00 PM PT, all of which are by 5:00 PM local time, are acceptable.

Effective March 16, 2018, the "in the afternoon" posting (which must include credits) was moved to 4 PM ET.