Leadsled,
Can you give me a specific example.
Fundamentally, the measurement and use of oil temperature is an indicator the rest of the engine is at a "suitable temperature" for high power use.
Think of the modern motor car, very good synthetic oils with viscosity index improvers give 5W-50 or 0W-30 kind of oils where as once they were 20W-50 and before that straight mineral oils. Today the car engine goes from start to out the street and "give it the jandel" so to speak. (young Scotty will never live that down).
So my feeling is that the oil temperature you need for a mag check, is not as high as you want for takeoff, but in both cases the numbers are very fuzzy in reality. This is not my area of speciality, but I can see with the use of say Phillips 20W-50 or Shell 15W-50 you can safely apply full power with the oil temperature lower as the effective viscosity is appropriate from a lubrication and pumping point of view.
The next issue is the upper engine components which is referenced to CHT, and here again there is a bit of variation from many OEM's as their is for MAX CHT as there is Min, but I find it hard to taxi out and go without the CHT being in the range of acceptable to all OEM's. On a cold day the oil takes longer to come up, but it does not take long to get to or over 75dF which is a fairly universally accepted minimum for operation above 1200RPM.
As for what the oil producers say…….never paid attention to that but I may be about to learn something. Remember the oil temperature varies depending at what point in the system it is measured. So who knows what the oil companies are referring to. Could well be they are all in the big fuzzy tolerance band of acceptable
By the way….in the APS class there is one topic that is made clear to be off limits….OIL. We suggest buy the one that comes in a bottle colour your wife/kids/neighbour likes, so long as it is a suitable grade aviation oil.