Whew; let me try this:

Operationally, there will be income and expense. The fees are not deducted from interest and dividends. They are part of the P&L. If there was, for instance, rental property, there would be operating income from the rent and operating costs or expense from the operation, such as utilities, landscaping, etc.

Capital gains and losses are from Assets. For example, if you acquired rental property and there are expenditures such as fees associated with that acquisition, they might qualify to be part of the Basis, or invested cost. Then, when selling or depreciating, that total invested (basis) is used for determination of Capital gain or loss. They are not a write off directly, but are associated with what you got for that cost.

So, to review: fees and other recurring events are expense exactly because they are recurring and ongoing as part of operations; or, they relate to the entity, not to any specific investment or asset. That's why I teach it as Expense Vs Expenditure.

And look at the phrase Capital gain or loss. The word Capital helps you realize it relates to funds. For instance, paying an electricity bill = expense, because Poof! That was all used up. But putting in a swimming pool is an investment in that new Asset. That money is not all gone; it's right there, invested in that pool (capital improvement).

That means you need to determine what are these fees and costs and where do they fall in the tax regulation provisions.

Hope that helps.