You have to look at the heat index value to get proper ambient temp to see if the system is cooling up to specifications.
Here's an example. We often have weather at 105-110 during the summer but it's very dry typically 25% RH. According to the heat index 105 F @ 25% RH has a heat index value of 108 F per rams specifications the drivers side center vent discharge air temperature should be somewhere around 62 F my truck with the shutoff valve installed will get down to about 47 F in these conditions. For comparison the heat index for a place with 105 F air temp and 60% RH has a heat index value of 149 F. Rams spec tops out at 110 F with an acceptable drivers side center vent discharge air temp of 64 F. Basically the air blowing out of your vents can be well above 64 F if the heat index is above 110 and Ram is going to tell you the conditions are outside of the design parameters and to kick rocks.
The specs for the AC system are very generous in the manufacture favor. I have attached the testing a diagnosis manual so you can see for yourself. 55 discharge temp at 100 F apparent is attainable even without closing off the heater hose for most trucks. There is nothing in the spec for an acceptable delta between the passenger and drivers side. As long as both vents are below the acceptable temp for the calculated apparent ambient temp the truck is operating within spec and the dealer isn't likely to do much beyond this. I wouldn't expect to see a TSB come out to fix this issue because the odds are when testing these systems they meet the minimum specifications even with the known problem of heat leaking into the drivers side duct work. GM did this same crap with the Chevy shake issue. Trucks were obviously shaking when they shouldn't have been but the amplitude of the vibration was below GMs NVH spec so they did nothing to fix it and owners were left with a truck that vibrated a 68 MPH plus.
I'm going to roll with the manual valve this summer and see what if anything comes of the AC issue and what Ram does. If they haven't addressed the issue by next summer or if the medicine is worse than the illness, meaning their ultimate fix is to pull the dash out and replace the blend door, I'm just going to put an automated bypass valve on the heater core hoses that will be controlled by the ambient temperature. Basically if the ambient temp is above 80 F the valve close and bypasses the heater core below 80 its open for water to flow through the core. My hope is this is ultimately this is along the lines of what Ram decides to do to fix the issue so that the valve is integrated into the truck and warrantied by the manufacture. I'm not going to hold my breath though.
Heat index calculator ( use the one on the right for relative humidity) most weather apps will give you the RH for the day.