Well, if you are convinced that the nCore is the problem, by all means replace it.
Just do the same tests with the replacement nCore. I would be surprised if they weren't the same as before the replacement.
And, quite frankly, if they are different after the replacement, it would be great for the rest of us to know that.
Personally, I think you are seeing different values based on the different frequencies being transmitted on each antenna. The Inspire 1 uses BOTH 2.4Ghz and 5.8Ghz to transmit and receive.
From the specs:
So 2.4Ghz transmits at a MUCH higher power level than 5.8Ghz does (900Mhz is for Japan only, so it is ignored).
The respective frequencies do not "share" an antenna on the aircraft. Only the remote controller shares an antenna and that is ONLY when doing Master/Slave communications BETWEEN the controllers. That is why the GL658C tanks on later firmware between controllers, as they dial down the transmission power for the video feed on those later revisions which is hard to receive on the Slave controller due to the shared nature of the one antenna. Again, all of this is well documented by plenty of people on here. Donnie Frank has also posted a number of videos talking about the failed video reception on later firmware revisions.
Also, to clarify, even if you downloaded the v01.08.x.x firmware in 2018, it is the same radio module as v01.11.01.50 that was released back in 2017. So of course it would have the EXACT same power levels. That is why I pointed out several times that you CANNOT trust the firmware off DJI servers for older versions as they are "hacked" to include the later radio modules. The revision will come back as an older revision in SOME of the firmwares, but upon inspection they are the SAME module as the later revision firmware. Again (and for the last time), DJI is forcing people to run the radio modules they want you to run. The ONLY way to run an older revision is to find an older repository with that older revision.
If you look at the firmware threads on here, there have been some very in-depth dissections of the firmware revisions and what they do and why.
FACT: DJI reduced power on the Inspire 1 with v01.10.x.x and above. ALL firmware posted by DJI AFTER v01.11.x.x came out were modified to include the radio modules from v01.11.x.x (so even revs as old as v01.06.x.x have the v01.11.x.x radio modules). Going by revisions posted during the logfile created during the update is insufficient, as you must get the checksum of the module loaded to see EXACTLY what was loaded. There are interim firmwares posted by DJI that included the actual v01.11.x.x versions in a v01.08.x.x firmware image. DJI went back and remodified it so that the module reported an earlier version, yet the checksum still proves it is the later version.
Again, I personally have done all this work trying to track down the stupidity with DJI firmware. DJI does not care about engineering standards, best-practices, or anything else. They will publish what they want, how they want and do not consider the end-user in any way shape or form, outside of "you will run what we want you to run". Just look at how many people have bricked cameras with firmware updates. That happened because they changed hardware in cameras and never went back in and re-rolled firmware to include those changes, so if you do an update to one of those newer cameras, you WILL brick it. DJI knows this and that is why they have been replacing cameras ON THEIR DIME! It is not "good customer service", but if they did not (and I am sure that will come to an end somewhere here) I am sure they would get sued since it happens far too often. Personally I just got back a few months ago a X5 camera that had the same thing happen. I WILL NOT use that camera to do a firmware update. Actually, I use a MUCH older camera to do all my updates, one that actually WON'T take the firmware update itself (yeah, yeah, I found some loopholes on how the firmware works in all my research) and thus I am not risking anything by using that camera in ANY of my Inspire 1 setups to handle firmware updates.
No-one is trying to tell you that you are wrong. We are posting up the technical information so that you can succeed in whatever problem you have. Do I have a RF power meter? No. Do I care to spend money on one, no. But until you post up the issues you have been having and can verify that you, in fact, have found a problem, posting up an "assumed" issue and then arguing some facts that some of us know are already flawed (like firmware off DJI servers) is only going to create even more issues, as people, in general, a extremely lazy creatures and will read you post and make the *assumption* that their problem is the same.
So, to pose the "real" question: Do you have any issues with your Inspire 1? Is it a "range" issue? Is it a "video signal" issue?
See, the later two parts of that query are already known. Firmware v01.10.x.x and later have reduced power radio modules. They also have totally changed flight restriction and geo-fencing modules.
What you describe as "issues" with older vs newer firmware are actually partially dealt with in the cameras themselves. I have personally found that running the v01.08.x.x/v01.9.x.x aircraft firmware with the latest v01.11.x.x CAMERA firmware results in the best options overall. The cameras are "fixed" with the latest firmware and the aircraft is running an unrestricted radio firmware. You must ALSO pair the aircraft firmware with the proper controller firmware (which you state will cause a cable-connected DJI Focus to have issues, but personally I have found a RF-Slave connected DJI Focus, via the Focus Expander, does not).
So, ultimately, I think the BIG issue here is that you want to run the "latest and greatest" that DJI offers. Go right ahead. You will have reduced power and range. Your reasons are you reasons. No one is arguing that. But, *I* highly doubt anything you are seeing is "out of the ordinary" and would really like to hear if a swapped nCore would produce different results. Just be sure to reflash the latest v01.11.x.x firmware to the nCore after it is replaced so it is an apples-to-apples comparison.