When is a flight delay not a delay?

I checked in for the LAS-LGW flight a little while ago - It's the 16:05 flight home.
My e-ticket says 16:05.
The monitor says "scheduled" 16:05.
EF.com says 16:50.
The monitor ALSO says "expected 16:25".
So, I take that to mean a delay. No probs, s**t happens, etc - and it's only 20 minutes.
But here's the thing, my boarding pass says 16:25 under "time", and the boarding time matches to the 'delayed' departure time. So someone, something, somewhere knew about this a while back - I didn't realise they dynamically adjusted the timing on BP's...
[:w]
So, what gives? Is it a delay? Is it a con? [:?]
My e-ticket says 16:05.
The monitor says "scheduled" 16:05.
EF.com says 16:50.
The monitor ALSO says "expected 16:25".
So, I take that to mean a delay. No probs, s**t happens, etc - and it's only 20 minutes.
But here's the thing, my boarding pass says 16:25 under "time", and the boarding time matches to the 'delayed' departure time. So someone, something, somewhere knew about this a while back - I didn't realise they dynamically adjusted the timing on BP's...

So, what gives? Is it a delay? Is it a con? [:?]