You're absolutely right. When pressing Caps Lock +K, I hear 20, 20, 75, 75.
So have I understood correctly that when a key command with two keys works as it should, one will hear the modifier key, so to speak, first and last, but if it says the modifier key, in this case Caps Lock which is 20, two times consecutively, it would not work as a modifier key in this case?
Here anyway some more test results:
Right Control+K: 162, 75, 75, 162
Left Control + K: 163, 75, 75, 163
Left Shift + K: 160, 75, 75, 160
Right Shift + K: 161, 75, 75, 161
For all other keys I tried, § to the left of 1, Print Screen, Delete and some others, it said the other value than 75 twice before 75.
Does this all theoretically mean that I could have Left Shift as an NVDA key and do everything Shift is needed for with the right one? Not convenient, but maybe kind of doable, since right shift is rather big and the keyboard itself small.