Note that the description just below each delay calls out how they are used but not so clearly.

Power On Delay is invoked when the IR function is named 'Power On' (I believe case sensitive).

Power On
Power Delay (10s)
Next IR code in your macro.

General Delay is used between 'Digit 0', ... 'Digit 9' for Channel Macros in cases where there are duplicate functions back to back such as:

Digit 2
General Delay
Digit 2
Digit 5

For channel 225.