The test was done by the communications team. Both units use the same LMR400 radio so in theory there should be no difference. With a LS with 1 watt of power being transmitted a RSSI of -43 dBm was observed with the internal antenna. With a LS+ a RSSI of -44dBM with the internal antenna was observed, so no significant difference.
I knew there was a difference early on in the LS+ with the radio needing the external antenna. That was also compounded by a radio issue with the T3 when it first came out. I was not sure of all of those issues have been resolved.