if the heat shield is offset too much most of the heat is offset and not spread and with the temp sensor on the LEFT if most of the heat is diverted RIGHT......
the ideal thing to do is-do you have a 3rd party thermometer with a few temp sensors? say 3? the bowie is big- weber has one that does 4 temps at the same time. i
set one ~6" from the left side of the grill- centered
set one ~ 6" from the right side of grill- centered
set one in the middle- centered- can be skipped if need be.
IDEALLY all 3 will show the same temp. and that temp will be the SAME temp as what the electronic sensor on the grill is saying.
ignore the grill sensor for now.
set the grill for say 250
place sensors, wait 15 minutes until temp reached
read the temp on the 3rd party thermometer
if temps are EQUAL, then compare that temp to the grill temp (use the APP) use the settings button to adjust the grill to match the 3rd party
if temp on either side is higher, slide the heat shield towards the high temp side about an inch if there is a WIDE discrepency in temps. half inch or less if small...
wait 5 minutes for temp in grill to stabilize.
check 3rd party... Adjust shield as necessary. Even a small 1/8th of an inch adjustment can affect the balance of the temps significantly throughout the grill surface.
Once the temps are GOOD....MARK the position of the heat shield on the FEED Tube on the left side with a sharpie or other perm. marker (or measure with a measuring tape and write it down somewhere it will not get lost, because when you clean the grill of ashes....you have to remove the shield.