Lol...then you have to go and test it. It’s not cheap to do it correctly.
You need the base oil (A oil) you are testing. Then before you run the B oil for testing you have to run a cleaning oil. There is an expensive oil some people use but there is other options. I’ll see if I can find in my notes the name of the clean oil and what else they use. Once you do all that, you can test the B oil. Then, so you aren’t guessing you have to run the cleaner oil again and then you can go back and test your A oil again.
And then, THEN if your numbers don’t make sense you have to run the test again!!! BTDT. You can easily spend 2 full days on the dyno just testing one oil.
On top of that, you have to have a dyno operator who has a clue. Coolant and oil temps have to been controlled very close or the numbers will be off.
It’s a royal PITA to test oils. And very expensive. It can be worth it if you are careful and don’t let the data feed confirmation biases and such.