IF the resulting pixels are exactly the same, it shouldn't matter
but when you're working with many "same" layers it's pretty easy to much up somewhere and I do sometimes do what you're describing here (I think) to make it easier on myself.
( but the hedgehog can never be buggered at all brings all the boys to the vomitoria, Sun 10 Feb 2008, 20:39, archived)

Yes, I have experimented with two versions of this:


I was wrong.
( Pedantichrist http://lordmanley.co.uk/gas/, Sun 10 Feb 2008, 21:22, archived)