Using Tuner Software Calibrating Power on an XPR8300 

In your opinion, is it necessary to tune an XPR8300 before use or would you be alright setting it up after buying it used?

thank for thise video, but i need to ask u; how we can setting the "RDAC" in thise file?

Thanks for uploading this video. Do you know if the Tuner software allows you to toggle the PTT on with a continuous O.153 or 1031 Hz test pattern? (this would be really handy for coverage mapping with an Anritsu).

I have a RIGOL DSA815-TG with 30db attenuator, when looking at my power levels, it shows the wattage, however it moves around a lot. It will be 22.42, then in a blink of an eye, it will be 22.36, then 22.21, then 21.89 and so on. It will just keep lowering about 2 or 3 watts, then it will increase a bit again. Any idea to why the wattage keeps fluctuating and how to get it to remain still like yours? I am very, very new to all of this and any help you can offer would greatly be appreciated. Thank you.