I brew a lot of German styles and have done several decoctions (single, double, triple), I rarely if ever do them these days mainly because, like Denny, I cannot discern much, if any, difference in the final product.
But also, similar to Denny, I'm lazy about things like this when I don't think it's a big flavor contributor. So nowadays, when I get that rare, wild decoction hair, I do a single decoction at mash out. I pull enough grist to fit into an oversized stainless mixing bowl. I drop that mixing bowl (with some loose foil over it to keep grain from clogging things up) into a pressure cooker, and let it go at 15 psi for 15 minutes. No stirring necessary and it works like a charm.
I've tried to hit temperature rests with decoction and have concluded that it's for the birds. Blichmann TOP is much better at this.