Trinity Tuner Tire Size Issue

Anyone else here have any issue trying to change tire size? The tuner only allows me to try it using Tire RPM (500-20000 and seems to accept my changes but has no effect on the speedo reading which is off by 4-5mph. I'm dialing it to 560rpm which according to the chart is correct. I tried dialing it down to the 500rpm minimum and still no change... The way I see it is if the speedo is not reading accurate everything else in the tune is gonna be ****.

It is weird it has you program it like that. My intune allows me to change it by the overall size or the metric size. The "problem" is it gets to 10% and then stops and says the tire size update failed every time. I only learned it actually was taking the tire size by mistake. If your tuner is up to date I would call the ever so helpful people at diablosport and see if they can help.

my Trinity would do it by overall or actual size not by rpm

OK, so I downloaded the latest .crom file. Went back and fourth to the truck back to the PC a few times to get everything updated to the latest and greatest. Ran into the PCM unlock (-34) error and ****** around with that until I figured out the tiny bits missing from the documentation. I was able to edit the tune and load it. All is well now and I am happy with the results so far.
Based on this experience and what I have read on here and several other forums, to me it does not sound like the majority of the issues people are experiencing with these tuners is due to the product itself but more related to the **** poor documentation Diablo Sport provides. I also think that the bad rep they are getting from a support perspective is due to what is probably a very limited support staff that is forced to put out fires all day. Once again I would guess there would be a lot less fires to put out if the documentation was more adequate.
For future reference: If you run into an issue getting your Trinity tuner to marry up to your truck and the PCM unlock error (-34) pops up. Start over again but this time when the tuner tells you to turn off the ignition, go ahead and do that but do not press continue until the dash lights go off and the PCM goes to bed. Only took me 5 tries to figure that one out.