I realize Mr. Cappe was talking about discussion papers under section 69 of the Access to Information Act. Those discussion papers, if they existed, could be exempt, as I understand it. But that is not the way cost information is presented. Cost information is presented as part of a memorandum to cabinet, and therefore it's a cabinet confidence when the bill is being studied by cabinet.
Evidence of meeting #49 for Procedure and House Affairs in the 40th Parliament, 3rd Session. (The original version is on Parliament’s site, as are the minutes.) The winning word was costs.
A recording is available from Parliament.