As noted way back by someone else, the burden of proof should be on the one making the (erroneous) claim that deferrals can't be made on comp over the limit. (Assuming the document itself does not have such a limit, which is unlikely at best but easily checked.)
The question here is not one of law or regulations - the question is, who is in charge and who is being paid to do what? The original poster needs to nut up and say "you're wrong because I know more about this than you do and I say you're wrong." And if they (I'm not paying that much attention...auditor or plan sponsor or whomever "they" is) still insist, then put it in writing and note that they are violating the participant's rights to make contributions and potentially causing plan disqualification by creating some arbitrary limitation not existing in the plan document.
Enough already.