ROBERTSUNRUS & 73shark,
My mistake, thanks for the catch! I was mislead by a tech bulletin put out by MB-USA in February 2013 that urged replacing the stock 20A fuse for a 25A to correct fuse blowing issues when starting in extremely cold weather. I believe this was a misguided recommendation. The starter will draw more amps when starting a cold engine but I don't think the current drawn by the solenoid would change much at low temps.
The tech bulleting was re-distributed by AEV (American Emergency Vehicles) and can be seen here: http://www.aev.com/uploads/file/SPRI...20START%20.pdf
I am now appropriately chagrinned
and a little smarter! So my day is off to a good start.