Changing oil and engine idling after long trips?

Y'all realize the op has a gasser right? And he asked about idling 15-20 sec??
Bam! Off topic again. Just like clockwork......
(Well my cousins brothers friends dog has a triple turbo ford Cummings with a 2 stage turbo timer and when it's colder than -19C warm up takes exactly 11.33 minutes if the automatic pressure sensing high idle feature is engaged in stealth mode which keeps the neighbors from complaining about the old 14 valve rattling in the campground. )