Hi again Chris,
I wouldn't worry too much about a couple of slightly 'out of range' results. The purpose of the exercise is simply to calculate the frequency 'error' of the particular dongle, by measuring the reported frequency of 'known frequency' gsm signals, so that the software can then tune the receiver to the correct receive frequency. With the TCXO dongles we are using for OGN-R, frequency error and drift are generally extremely low at around +/- 0.1ppm. The actual figure derived from your setup is reported on (ognpaw.local):8080 as RTL-SDR device / Frequency correction...... If this is reporting a significantly greater figure than the above it might be worth rechecking the scan, but otherwise things should be just fine.
You are correct by the way, Lee has already 'automated' the OGNPAW setup, including the gsm scan to save non technical users having to worry about all this, so this shouldn't normally be an issue. It certainly took me a while to get my head round it all with the early 'manual' setups.
In extreme cases, the figure can if necessary be adjusted manually within the 'config' file, by those who have the required knowledge / expertise.
Best regards
Peter