First off, thank you for sharing your thoughts and here is the answer.
Low trading volume happens because we don't have many users yet.
And fee amounts are predictable since each currency's trade volumes are publicly open already (You can see volumes on https://dovewallet.com/trade/spot/eth-btc )
The only thing that is not open to the public is user balances, but you can calculate from bonus rate.
If all fees are distributed then here's easy calculation formula.
(bonus rate) = (fee from trading) / (user balance)
(bonus rate) = ((trading volume) * 0.001) / (user balance)
We are distributing some portion of bonus from trading fee currently, not from our own pocket.
If you think the bonus rate is pretty higher than what you expected, maybe it means that user balances are lower than you expected.
There is no trick, hidden fee, or complex derivatives.