When to use Amber or Dark LME?

[FiercelyFuzzy]

Hi Guys

I picked up a couple of tins of Coopers Amber LME on the weekend with a mind to brewing up a porter or stout at some point. However, in virtually all the recipes I`ve subsequently found Pale ME is used & the colour is made up by steeping speciality grains. I guess I found this a bit surprising as what`s the point in manufacturers producing amber or dark ME when people just use pale + grains for darker brews?
So, could I just use amber + grains in a recipe intended for pale, or would the flavour be too intense? I guess I could buy a tin of pale & split it 50:50.

Many Thanks!
FF