Do you have some pics? Are you sure it's not ceramic instead of porcelain? What about the lippage on the job? Is everything good and flat with nothing sticking up? Enough grout used? What's the substrate? Any flex to it at all?

A PEI rating has to do with abrasion, and the surface's ability to resist abrasion, not it's ability to resist chipping. Hard things are often very brittle. Usually though, with proper installation, the propensity to chip isn't a problem as it's set in a supportive mud bed with grout occupying the spaces in between to create a monolithic whole instead of brittle squares subject to damage.

SO sorry it took me this long to respond; been very busy. I attached a picture. It is glazed porcelain, approx. 1/8 grout lines, lippage is almost nothing at this place where I took the picture. Lippage is 1/16 where I am certain the chip is from the toy car (not this pic). It's on concrete slab so no flex. No cracks at all just chips. I have about 20 tiles with chips. Installed a month ago. Thanks for your help!

Here is a pic of the tile that definitely was chipped by a Hotwheels car. Lippage is about 1/16.

The closeup looks a little shy of grout in the horizontal line. But, that could just be the way the shot is done.

Have you had the installer out to look at it? Or the retailer who sold it?

The tile in the 2nd picture is a little shy of grout. The other tile, however, in the 1st picture, has full grout. Most of the chipped tiles have full grout. The installer did look at it and said he would replace whichever tiles I am not happy with, but I am concerned that it will be a never-ending process because the tile is too fragile. I've never had a single tile that chipped before. Doesn't this seem like an excessive amount of chipping or is this normal for glazed porcelain? I think my previous tile has all been ceramic. Porcelain was supposed to be better, but not this batch. Any suggestions?

You need to get the retailer involved. This should be a warranty claim.

Looks like lippage is the culprit to me = installation-related failure.

I mean really, how hard is it to lay a level across each joint during the install, then increase setting pressure or pull-and-butter as needed.

Looks like the installer simply trowed thin-set, then laid the tile with absolutely no regard for lippage.

http://www.tcnatile.com/products-and-services/publications.html

Here is a link that might be useful: Pictures of Tile Lippage