The firm has made a number of criticisms of the draft guidance as part of its response to the regulator’s consultation on the document, which closed last week.
The response describes the draft guidance as being "too long", "piecemeal" and "unwieldy" and says the new online format used by the commission is unsuccessful.
"In its present form, the draft online guidance is difficult to navigate, with links leading sometimes to documents that do not form part of the guidance," the response says.
"We consider that it would be nigh on impossible for a charity trustee making use of the online format to be confident that they had ‘had regard’ to all the statutory guidance."
Nicola Evans, senior associate and author of the response, also questions a number of the commission’s legal interpretations of the public benefit requirement.
She says it would be helpful if the commission separated best practice guidance from legal requirements faced by trustees, which are both currently included in the draft revised guidelines.
The Charity Commission revised its guidance on public benefit after a ruling by the Upper Tribunal that aspects of the guidance were wrong. It launched a public consultation on the revisions in June.