I don't recall any of my predecessors performing such an independent cost estimate. However, I may be wrong, because in 2013, I was busy doing other things and I don't remember such an estimate. Again, that doesn't mean that it doesn't exist. It probably refers more to my failing memory if it does exist and I don't remember it.
Evidence of meeting #3 for Government Operations and Estimates in the 44th Parliament, 1st Session. (The original version is on Parliament’s site, as are the minutes.) The winning word was inflation.
A recording is available from Parliament.