My galaxy s3 has a similar issue. The 1X 1900 radio is 20 dB out so higher than ehdpd and usually higher than LTE.
Ex 105 for 1x and ehdpd will be around 80.
I took my s3 apart and there are burn marks on the motherboard and it smells like a blown capacitor does. So my problem is a hardware failure. Maybe it could be something similar to that.
Does it get really hot when using LTE or 3g for long periods of time?