Are the Voyager spacecrafts' X-band TWTAs currently set to high or low transmit power? How often were they changed?

Question

In this answer I discuss that the Voyager spacecraft can be commanded to use either high or low power to transmit to Earth on X-band.

Question: Are the Voyager spacecrafts' X-band Traveling Wave Tube Amplifiers (TWTAs) currently set to high or low transmit power? How often were they changed?

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Background:

From DESCANSO Design and Performance Summary Series Article 4; Voyager Telecommunications by Roger Ludwig and Jim Taylor:

3.3.4 X-Band Exciters

The X-band exciter converts the frequency at the output of the S-band exciter to X-band to drive the X-band TWTA. Comparable to the S-band exciter function, the X-band exciter phase modulates the RF signal with the composite telemetry signal from the TMU and, if the X-band ranging channel is on, the ranging signal detected by the receiver.

3.3.5 X-Band Power Amplifiers

Only one X-TWTA can be powered at a time. Further, a control input from the CCS ensures that the X-TWTA is powered off when the X-exciter is off. As is the case for S-band, whether powered on or not, the X-TWTA power level is selected to either of two levels⁴ by CCS control input.

In October 1987, the Voyager 1 X-TWTA-2 failed, as annotated in Figure 3-1, legend item 3. The primary downlink was switched to X-TWTA-1. In November 1998, Voyager 2 switched from X-TWTA-2 to X-TWTA-1 [6].⁵ For both spacecraft, legend item 1 in the figure flags the changes from X-TWTA-2’s right hand circular polarized downlink to X-TWTA-1’s left hand circular polarized downlink.⁶

⁴The low-power and high-power RF levels to the HGA for the X-TWTA are 12 W and 18 W.

⁵The switch to the backup X-TWTA is in status report http://vraptor.jpl.nasa.gov/voyager/pressrel/vg981117.html

⁶The relationship between X-TWTA selection and the resultant polarization of the X-band downlink is described in the SXA section that follows.

Foot note #4 indicates that there is at least one method to decrease the transmit power of Voyager built into the system. A command from the ground can instruct the X-band High Gain Antenna (HGA) Exciters to change between 18 W and 12 W of transmit power delivered to the antenna. But what does that mean in terms of electrical power?

Figure 3.1 from Article 4; Voyager Telecommunications (click for larger), discussed further in the question Frequency responses of Voyager's S-band high gain antenna's feed-horn and receiver front end & IF?

Answer 1

Both are used:

• low power for the 160 bps live telemetry: this is sent immediately, and not stored on board. This is done for at least 8 hours/day.
• high power for the high-speed tape playback. This is done 6 times a year for Voyager 1, Voyager 2 tape operations were ended in 2002. For Voyager 1, tape recorder operations will end in the next few years.

Three times per week, Voyager 1 has 48 seconds of high rate (2.8 kbps) PWS data recorded onto the Digital Tape Recorder (DTR) for later playback. Voyager 1 has six playbacks per year. The playbacks require 70 meter and 34 meter DSN support for data capture.

The lowest playback speed supported by the tape recorder is 1.4 kbit/s.

From Descanso volume 4, page 14:

VIM = Voyager Interstellar Mission (which began in the 1990s).