I think I may have found a solution to the LTE problem! Discovered that there is a crap load of info in the SignalStrength method which can be accessed by looking at the SignalStrength.toString() method. This will produce a string with space separated elements, example: "SignalStrength: 13 0 -120 -160 -120 -1 -1 99 2147483647 2147483647 2147483647 2147483647 gsm|lte 4". If you split that by the spaces, then the eight element *should* be the LTE value.
I created a "Test message" item in the list of submenus on the Main tab. It shows the unaltered values. I also created a method in my Util class that takes the RSSI value and, if the network technology is LTE, get that from the string and do the "-113 + 2 * signalStrength" calculation. I don't know if that last bit is necessary...just assuming it is. I'm going to need feedback from the users for this one since I don't have an LTE phone.