Unable to edit a recording in progress

When using my first DVR system from COX, i was able to edit a recording already in progress to add or remove time from a recording.  This was useful if i needed to add extra time to a live event or adjust a recording by a minute or two.

Why does the new Whole Home DVR system not let you edit a recording in progress?  This is extremely non user friendly by causing me to break up my shows into multiple recordings just so i capture the whole thing.

I am in the Wichita, KS area.

Thanks