I rememeber being told by a professor that the times manufactures gave were usually for diffuser enlargers, and that matched my feeble attempts at E.I. testing...
Both films I have tested (35mm tri-x and 120 macophot up 100) tested pretty dang close to what a diffuser would need on the high values, folllowing manufacturer's specs (efke specs for the maco).
To kind of enforce the point, I was the only one printing with diffusion heads in my class, and everyone else had to drop dev times at least 20-25% to print on condenser.

Keep in mind that my ignorance is only surpassed by my faulty memory, so don't hate me if I'm wrong.