Yes, for every withdrawal whether it is asymmetrical or symmetrical deposit, there is always a fee to be paid in native $RUNE to withdraw funds from the pool.
BUT, for NON-RUNE asymmetrical deposit the withdrawal fee will be native to the asset when withdrawing the asset asymmetrically.
I.e to withdrawing an asymmetrical BTC deposit will have a withdrawal fee paid in BTC.
There are 3 types charged on asymmetrical deposits:
The on-chain deposit transaction fee (inbound tx)
The liquidity fee as a function of slip
The on-chain redemption transaction fee (outbound tx)
Are there slippage fees for symmetrical deposits?
No, there is only the deposit transaction fee.
How are fees calculated? It is important to note the current congestion of said asset you want to swap, as gas fees on ETH and congestion on BTC will affect how much fees you will pay. This will improve when depths of liquidity pools increase.
The other chain’s network fee is out of THORSwaps control and is due to efficiency of their native network. i.e to swap Native BTC to Native ETH directly on THORSwap -> you would pay BTC network fee, ETH network fee, and RUNE network fee.
Compare it to a swap from Native BTC -> Wrapped BTC -> Wrapped ETH -> Native ETH. You would pay multiple transaction fees using ETH. When you swap to an L1, you pay the outbound gas fee on that chain with a 3x premium.
Where does the 3x premium come from?
1x doesn't work as the system would be at a loss, since it uses 1.5x the advised gas. 1.5x wouldn't work because the system would barely break even. So it charges 2x what the nodes use (1.5x) and pays the LPs back for ACTUAL gas.
The margin, 1.5x, is system income. The fee structure has a fixed component and variable component on the tx size. On those 3x of the gas outbound chain, there is half of that is going to the network and LPs as a "network fee" (1.5x) and the outbound transaction has the other half (1.5x) of that fee to use as gas on the chain, so its up to 1.5x the average current gas to make sure its a fast transaction.
Transaction Fee = Inbound fee Network Fee = 3x fee charged by network Total = Sum of both