Aluminum Differential Cover Thermal Results

I replaced the differential cover on my 2009 Ford F-150 with a similar aluminum oversized cover. I replaced the Ford fully synthetic lubricant with another brand of fully synthetic lubricant. My brother-in-law was towing a similar trailer with a similar truck with standard differential cover and synthetic ford lubricant. I had checked both differential covers while I was using my stock for cover and the temperatures were very close. After the installation of the aftermarket aluminum cover I only saw about a 10 to 15° drop in temperature. I know it's not scientific research but it's my findings for what it's worth. The main reason I installed it was ease of changing gear lube.