ETA's changed enroute

I have never been on duty while transfloing(SP?) and no one has ever said anything. MY routine is this. I show up at a shipper or Consignee and go on-duty right when I send in the arrival call. I then go talk to whomever and get told where to go and what to do. The second I get back to my truck, I go to line 2 SLeeper berth, whether I'm waiting for a door or backing into one. When I get a green light or my paperwork is brought to me, I then go to Line 4, on-duty and I stay there until I'm rolling onto my next assignment. On average about 1/2 hour to 45 minutes on duty time per Customer. I have been very lucky that I have only had one Driver Hand unload in the year that I have been here.
Fueling only takes me 6-9 minutes and then when I pull out from the pumps, I go line 1, and walk into the Store and Pee, and get treats, whatever.
Pretrips take anywhere from 15 minutes to 45 minutes, depending on what I'm doing. Sometimes I get a slack adjuster that I get paranoid about or cleaning my windows takes longer or I have to air up some tires.
Post trips, 5 minutes. Schneider is the only Company that I have ever logged on duty time for a post trip. I always just flagged it and never had an issue anywhere else, but here

 

But the ETA changing does really irritate me, as does the NAT changes, those really set me off! I'll have accurate times and they'll change the Preplan and then the NAT gets screwy and says that I have 67 hours available after being on duty for 5 days