When shoping for my youngest son I bought a 3 lb chub of 80/20 ground chuck at the local WAl Mart.
He livies alone so he can skinp on the beef somewhat.
I got the chub home and in the prep. to section it out I out it on my scale. It was only 2lbs 12oz.
Indiana law says if you package at a net weight it must be at least that.
Try to contact Wal Mart customer service on a weekend.
The "acting store manager" was zero help.
Looks to me that Wal Mart is selling short, 4 oz is nothing unless you think in the quanity they sell.