By cleaning you will reveal all the problems that exist. You job doesn't look to bad but looking at the pictures, I would be sure to show the Home Owner the little crack next to the tile.
A close inspection - of the grout lines and chips in the tiles etc. Tile edges not level ....get a tap...if it sounds hollow it has detached from the subfloor. Grout shrinkage is usually caused by acid cleaning products used by house keepers and home owners.
The pre-inspection is really important to make sure their problems do not become your problem.