I have used this program a lot since purchasing the 4423 Pico.
It has always provided pretty accurate data as far as I could tell in the past as I don't normally do mechanical test to compare the results.
However, the last two releases have been giving me very suspect results. I attached an example of a test made 2 weeks back with the latest software. This morning I installed the older 1.2.1 alongside the new version and opened the same file in both versions of pico diagnostics and you can see clearly that there is something a little askew with the new version. With a mechanical test this vehicle had even compression with a less than 5% variation.
I thought I would bring this to your attention although I am sure you are already aware of the issue.
In the meantime I will resort to the old version, with anticipation of the new release