@C_Geil
If you're billing a tenant for charges, it's odd the link that item to an expense account because that's income to you. The warning you're getting is just saying "if you do this, you will be reducing your expenses, not increasing your income." The net effect is the same but you should record the tenant charges as income and the actual expenses you incurred for the cleaning/repairs will be recorded when you pay staff/hire vendors/order supplies, etc. for the work.
