You are not doing something wrong. VORs are are supposed to tune to the same frequency on both sides most of the time. Dedicated DME receivers that are capable of tuning to several DMEs are used for NAV position updates.
Yes, the packs do configure for high airflow when the M/D switch is set. Unless if they air already operating in high airflow, which is the normal mode of operation in most cases.
There are 4 pack flow schedules and the Air Supply Controller selects the appropriate one for the conditions. Schedule 1 gives the greatest airflow and is the usual flow schedule. Schedules 2, 3 and 4 give less air to the packs and are selected under some specific conditions (like during take-off, single engine operation, wing anti-ice on, cargo fire switches armed, available bleed air less than usual, more then the normal number of bleed air users systems etc,)
Setting the M/D Flow selector will override the selected schedule and set schedule 1.
Duct pressure has nothing to do with packs airflow. Duct pressure is regulated to a fixed target by bleed valves regardless of selected pack flow schedule.
Packs schedule selection and actual airflow is continuously calculated by our simulation of the pneumatic system and the airflow volume level is accordingly adjusted.
However, it may be very hard to hear the differences because the changes are usually small (for example schedule 2 flow is 15% less than schedule 1 flow) and are masked by the high level of the recirculation and the equipment cooling fans volume.
And of course, if packs are already operating at schedule 1 (which happens most of the time) there will be no difference at all.
Read the introduction manual pages 0.00.86 and 0.00.87.
It explains in detail how the COM radios operate and also provides options to solve any problems you may encounter with 3rd party add-ons
