thanks for the comparison.
A short remineder. It's reading jitter, not disc jitter. So it's always a function of what' son the disc and how the drive performs.
As such, two different drive models with different PUHs, algorithms and other parts are very unlikely to agree on jitter.
Even scanning with exact same models (two specimens) is bound to produce some variation. Even one drive and two scans will produce some (hopefully neglible) variation.
From these you can calculate the average and the standard error very easily.