Arrow:
right you are, in fact it is more than "generally" it is the case almost exclusively where doubles are regulated in the manner you describe.

In terms of speed for firing the front trigger first, it is faster ( albeit slightly ) to fire the front trigger first and simply skide your finger to the back trigger. as opposed to firing the rear trigger first, extracting your finger, placing it on the fore trigger and firing again.
the natural tendency is for your trigger finger move rearward rather than forward.

I have shot several doubles, not near as many on here I'm sure, but I learned to shoot db shotguns with two triggers and I can say that other than one mechanical failure of a db Brno( in 458 win mag) I have never had a double, double on me

DT