Remember ZDDP ratio is also dependent on the weight of
oil used , and you can get ZDDP as an additive too. (in a little shampoo bottle)
The ROUSH oils and they ( as well as Mobil1) vary the ZDDP content by weight.
5w20 -600PPM -- 10W40 -- 1300PPM, 40W break-in
oil like 1800ppm.
Have not used the Joe Gibbs stuff myself.