01
Service fees belong to the platform; network gas pays for execution; token taxes come from token rules. Slippage is the difference between expected and executed price. Slippage tolerance is a limit, not a fee charged in full every time.
02
In a fictional $100 trade with a 1% platform fee, that fee is $1. Gas, token tax and price impact still need separate checks. This example is not the rate of any listed platform.
03
Compare expected received amounts at similar times, on the same network and at the same size. A failed transaction may still spend gas. Before increasing tolerance, examine liquidity, token restrictions and changing quotes.