dudes smoking crack.

You have no worries as the synthetic you are currently using is WAY better than the grades and certifications of the very best dino oil back when your engine was designed.

There must be a reason they are making that claim, such as they sell some special oil? I met an engine builder one time that swore it was the worst thing ever put in an engine, a discussion even made him start arguing with me. He said "have you ever seen an engine that ran that crap in it?". Uhhh yes sir, can I have my gasket kit now?

Never went back there.