it is really six of one half dozen of the other.
If you mark the filing fee paid as an expense then the customer payment of that fee is company income. On the P&L income is reduced by expense
or
if you create an asset account called fees-due and use than when paying the fee for the client, then when it is paid to your company, you post the payment to the fees-due account to zero that entry out. This part of the transaction does not hit the P&L, but the effect on the bottom line is the same as the first option.
My preference is to use the asset account scenario