Unless your remark is a joke (ha-ha), CB radios are limited to 4 watts RF output. Why are you admitting to using an illegal linear amplifier on this board??
On a more serious note, my understanding of TIS is that stations are permitted up to 10 Watts transmitter output, but there is a maximum field strength limit that they also have to meet. The WQWS230 antenna system must be working pretty well for a TIS antenna, since the station had to fold back power.
In downtown Hillsboro, I can hear the station relatively clearly using a loop antenna. The signal strength is not enough to stop scan on the radio in my car, although the audio is intelligible when away from utility lines).
The recent rainfall must have improved the efficiency of the WQWS230 ground system. From Cornelius Pass Rd. in Hillsboro (near the Harvey statue), 1610 was stopping scan on my car radio. 1640 was having trouble doing the same.