Mercedes tire pressure changed from being 32 as the highest to 47 as the highest?

I am now on my 6th MB.  Perhaps your pressure gauge is not working. Stop at a gas station and check your tire pressure, then you will know if the car's gauge is working.

Are you saying the reading was 32 but it now states 47 PSI?  If so, sounds like you have a faulty TPMS unit.  Verify correct pressures with a tire pressure gauge.

BTW, the correct tire pressures differ between front and rear.  Depending on if this is a E-sedan or E-coupe, and what size tires you have, but the recommended rear pressure can be as high as 46 PSI.  Consult your owner's manual or the inside of the gas flap door for the correct pressure.

MAY BE A DEFECT of some kind! Are you using the TPMS as a guide here! use a real TIRE PRESSURE tester at each wheel to see if they are CORRECT!  

Tire pressure is posted on the door frame and it is something at or less than.  Look at your tires.  Its says 40 pounds Max on them.  All tires are 40 pounds Max.  Have been for years.  Don't know why you have this confused.  btw  The only time you use 40 pounds is when you have a ride to five of the biggest guys on the football team.

Steve H , I’ve been driving 40 years. In all the time all the cars I’ve had have had recommended pressure from 30-35 psi, mostly 32-34. Never heard of a car using 47psi unless it’s a space saver spare.

Set them with a tire gauge. You can't trust the readings on your dash.

You are reading the maximum pressure the tire can safely handle listed on the sidewall of the tire. This is NOT the pressure recommended by Mercedes. The recommended pressure is listed on the driver's door post or in the owner's manual and does not change. 

You bought different tires.  The max pressure on the tires is irrelevant.  Your tire pressure should be close to what's recommended for your car which is usually posted in the driver's door opening.