Over the Counter Zinc Additive

I used VR1 for several years beginning in 2003. About 5 years ago, my engine builder, along with a couple others locally, put out the word that ZDDP had been reduced in VR1. I called Valvoline and they told me that was not so. I chose to believe my engine builder and started using the Schneider additive. All are free to make their own decisions.