Well...let' go one step farther. Why is torque always shown with a range of values? Why not just one value? I have always torqued to lower, and checked to higher. If it doesn't move, then you are good.
I also have to ask what your reference is for "loosening". Have you seen it in a manual anywhere? I see it is rampant all over the internet, but so is a lot of mis-information too.
I looked in my Stockel "Auto Service and Repair" manual, which was the teaching source for tech schools in the 1960's through the 80's. It goes into detail in every operation. Under "retorquing", it only says that, "some assemblies should be torqued after a certain period of time". It does not say loosened and retorqued...just "torqued". I find loosening any gasketed part to be problematic. You go to great trouble to torque the part in the proper sequence and ramping up in thirds to prevent warping or cracking. Why would you ever want to loosen a bolt unless removing the part and discarding the gasket?
I have a degree in Engineering Mechanics, and was taught how to determine bolt size and torques vs. materials. We were taught use lubrication on all bolts for installation and torquing, unless contamination was a factor. I was never taught to loosen a bolt to check torque. I never heard of loosening a bolt to check torque until the internet became common.
Not trying to pick a fight..just trying to learn. What reference have you guys seen to recommend loosening bolts to check torque?