Since I've been on a Noack tear lately, mostly due to having 2 GDI engines, I've noticed what others have said in the past about Noack testing having a margin of error. Noack is an approximate figure. It's not the end all, but it is something to consider. Also, companies will play games with this number and obviously choose the lowest value they can obtain.
Just for fun, here are some examples from an independent lab and the product data sheet comparisons. The data is from the YouTube channel which has been very consistent.
Amsoil SS 0w20 PDS - 8.5%
Lab Tested - 9.5%
Amsoil SS 0w30 PDS - 8.8%
Lab Tested - 9.5%
Redline 0w20 PDS - 9.0%
Lab Tested - 9.4%
Ravenol 0w20 ECS - 7.4%
Lab Tested - 7.5%
Just for fun, here are some examples from an independent lab and the product data sheet comparisons. The data is from the YouTube channel which has been very consistent.
Amsoil SS 0w20 PDS - 8.5%
Lab Tested - 9.5%
Amsoil SS 0w30 PDS - 8.8%
Lab Tested - 9.5%
Redline 0w20 PDS - 9.0%
Lab Tested - 9.4%
Ravenol 0w20 ECS - 7.4%
Lab Tested - 7.5%