Yeah seems like that's that's their theory for the Topping's inaccurate PEQ.Ha, well that's true re the 5Hz offset, that can be quite easily seen when I look now, I only gave it a quick scan last time! Yes, I agree, the Topping is slightly off for some reason - and according to the post you linked then that sounds like something akin to "rounding errors" if I understand his post correctly?
Linear distortion (i.e. frequency response accuracy, what really matters) with PEQ engaged wasn't examined in this review, only nonlinear distortion / noise.@GaryH amir didn't have any issues with his peq tests!