Phillips screwdriver specification on screw heads
Mechanical items get manufactured to specific tolerances.
You manufacturer's items may well be within tolererances required, and have passed manufacturers inspection. Therefore, the manufacturer is not likely to be...wrong.
If you need deeper phillips driver seats, it may be a good idea to talk to your manufacturers representative about your problem, rather than prove someone...wrong. This will get you help a lot faster. Play the underdog at times.
So much for attitude in manufacturing circles. People are always willing to help,but they don't like to be proven wrong.
Mass produced items are being produced in batches of 10,000 or whatever the number. The manufacturer may have different batches with deeper seats.
Switching manufactureres or brands or quality may be the way to go.The cost of not being sure may be greater than the savings buying fasteners cheap.
It would only take a few seconds and inspect the depth of the phillips using a $25 surface plate with a drop dial. Installing any screw takes a lot longer, and it takes even longer when the batch comes in different depths. Send the shallow ones back.
Also, different phillips tips can be used. They need to be matched to the seat available. The tip of the phillips driver can be ground down a bit so it fits deeper into the seat. I would almost bet that....... THIS MAY BE YOUR SOLUTION..... to the problem. Just a guess.
Just a few ideas.