Hi @887155 ,
it seems the .com1 and .com2 commands don’t accept any explicit 8.33 kHz frequencies.
When I try to enter e. g. “.com1 122.805” it won’t set this frequency in the COM panel. Any non-8.33 kHz frequencies work without problems, e.g. “.com1 (or .com2) 122.650” will tune this frequency.
Using stock MSFS, and usually dialing frequencies directly on the COM panel, but would be great if this could be corrected/updated. 
This is a historical limitation of SimConnect. It uses a format for setting frequencies that only includes two decimal places of accuracy, so it cannot work with 8.33. It should still be updating the frequency shown in vPilot, though, so you can still communicate with ATC on VATSIM using those 8.33 frequencies.
Note that the above is true for the older sims that vPilot supports. MSFS has introduced a way to tune 8.33 freqs through SimConnect, and I will update vPilot to support it with the dot commands at some point, but it’s not critical because for MSFS, if the aircraft supports 8.33, you can just tune the frequency in the aircraft anyway, and the dot commands are not necessary.
I had the same problem with vPilot so do this. In the remarks type .com1 122.105
Nothing else, that will do the job.
Thank you for explanation, I was looking for it due to having the same problem. This would be a very useful fix. I use .com# commands regularly even though I have MSFS and even have a hardware radio panel, as typing a command instead of dialing a frequency saves a lot of time. During a very busy approach, when you are almost overwhelmed with monitoring the flight, airspeed, entering parameters into autopilot, etc., dialing a frequency can be very time and attention consuming (especially if need to switch something like 134.905 to 123.455, lots of spinning for decimal part), and you can’t always prepare, as additional controllers might come online, or you are given a frequency you didn’t expect. I remember getting a frequency, dialing it, and when I immediately reported the controller asked me why I didn’t switch for so long (was an approach during a very busy event). So allowing to use .com# commands for 8.33 spaced frequencies would be great!
The .com# commands already do allow 8.33 freqs. They just don’t update the value shown in your sim’s radio stack. But vPilot is indeed tuning the 8.33 freq so you can talk to ATC.