Indded so. I suppose that those who (unlike me!) are concerned about VD might 'recommend improvement' (i.e., give a C3) but, as you say, I can't see how anyone could justify more than that.And if we look at an EICR it asks for "Potential danger" and it would be hard to say excessive volt drop is really a potential danger, so one can hardly fail an installation on excessive volt drop.
... and don't forget that when calculations (or measurements) indicate that VD in a circuit might theoretically be a little more than the guideline figure, that would only ever actually happen in the 'worst case scenario' of a 'fully loaded circuit' - something which is very rarely going to happen in practice. Hence, even if calculations (or measurements) indicate that a VD 'beyond guidelines' is theoretically possible, in practice that will probably never happen.
Kind Regards, John