This is why you always install control joints in cementitious flatwork-they direct where the quacking will take place. Without them, quacks can randomly occur. 
d&r 
You can put in the control joints, but sometimes the things quack wherever they want anyway.
Which puts the masons in a fowl mood.
When I worked for a home builder , we would normally have to do some rework on cement basements that were in need ,and used a product called fastcrete ,which is probably just another franchise name of some of the other products mentioned.
It was mixed with water , poured and would self level , but pouring to the lip of the hole , would yield a small depression about a 1/16 of an inch , as indicated on other posts , you would have to over pour by a certain amount , and was almost an art depending on what needed to be filled.
Declan
I was going to feather my cementitious joints in the hopes of not running afowl of this problem. Apparently my goose is cooked anyway.
Thank you for this word. It not only sounds cool but also looks cool
Scabble : great word for Scrabble. OR Boggle 