Yes, you are definitely playing in a different sandbox then. Also, even smaller projects at Universities many school systems, hospitals, industrial complexes, etc.You have not been involved with many larger projects have you? GC's like Turner, Bovis, and the likes scrutinize every aspect of the bids and on these projects the MEP group is constantly involved through out the project, sometimes on a daily basis. I have been on jobs where each part of the architect and MEP group had a QC person on the site everyday. As far as VE negotiating, it is done after all the contracts have been awarded and the owner is part of the process. Most jobs of this size have Architect, Owner, Contractor meetings weekly.
During AIA progress billings it is not uncommon to have to walk an MEP rep through the stored material and check off schedule of value items.
I know this is not typical of small to medium size jobs but on large projects it is pretty much the norm