Sack the project manager. If he can't lay a straight edge onto a floor before asking a tiler to tile on it then the shouldn't be doing the job. Sorry - but you really did ask for it. You level the floor THEN lay the tiles. You were the boss - he was your employee.
Joe you are talking through your hat mate,if a tiler of 32 years experience cant be bothered to check the substrate himself before starting the job then he should look for other employment.
Your basically saying that if the surface isnt prefect then its ok for the tiler to leave a poor job and as I previously said any DECENT tiler will be able to level up anyway.