Over the Counter Zinc Additive

Understood. I suspect with all the unknown's around ZDDP (how it works exactly and how much is needed), the Hughes guys want the best protection they can get from returns or failure of their product.

You're right... it does not stand to reason that a roller would need the high ZDDP..... that is touted as a reason that ZDDP can be lowered in new oils! In your shoes, I'd do as they recommend for break-in and then research things more to conclude if you really need it long term. I would be tempted to call them back and ask WHY they recommend it for a roller....and try to find out the background of who you are talking to... there are some less than knowledgeable people out there. Maybe it is for piston wear protection??