"Brought Forward" and "Pushed back"

During a conversation with a colleague about the time I had received an automated email, I noted that it had arrived 20 minutes late. I then checked the email schedule software and said:

The scheduled time has moved forward 20 minutes for some reason.

To which he replied:

You mean moved back

The discussion carried on with me arguing that the time had indeed "moved" forward. Time moves forward after all, and it was supposed to go out at 16:00 and went out at 16:20 instead. The time moved forward.

Now I completely understand his argument, and I realise that the standard way people generally talk about time in relation to meetings etc... is to say "It's been pushed back" or "It's been brought forward". But he wouldn't concede that my choice of words was a completely valid way to express what had happened.

This left me wondering if I was actually correct, and also why exactly we say "Brought Forward" and "Pushed back"?

Humans tend to talk about time with spatial analogies. If something is brought forward in space or time, it moves closer to the reference point, if it is pushed back it moves further away from the reference point. For time, the obvious reference point is now, and we face the future, so things are pushed back into the future, or brought forward toward the present. If we could move things in the past, this could be more confusing.

But that's talking about things moving in time, not time itself moving. When we talk about time itself, employing the spatial analogy, we say that time moves forward into the future. When we set our watches back, it's into the past, not further into the future. When we advance the date on our computer, it's into the future, not towards us in the present.

Anyway, I think that's the general idea and source of the different approaches. However, if you say the time of a future event has been brought forward or pushed back, the bringing or the pushing will tell you that the time is now closer or further away. Moving is more neutral is that directional sense, so is more likely to be differently interpreted.