Do I get it right on command ...
Each level of command provides 25% of its bonus value to the level below. Meaning that by default a fleet enjoy 100% of the bonus of its commander and 25% of the Admiral in charge of Sol Command (if you start at Sol).
If now I create an intermediary echelon, then the overall command only provides 25% of 25% of its bonus, as the new intermediate command provides 25% bonus. Meaning that it is theoretically possible to get less bonus overall, if the intermediate command is worse than the overall command.
Is that right?
Now for ground units ... If I have a unit with a bigger size than the HQ within, the commander bonus is reduced in ratio to that. So a HQ 10.000 within a unit of 15.000 size only provide 2/3 of the commander bonus.