Does you monthly bill accurately reflect your commercial lease terms? Often times it doesn't. Given how complicated commercial leases can be, it's not uncommon for the landlord to make mistakes and overcharge (or undercharge) you.
Monthly cost errors can be caused by miscalculations of shared expenses, like janitorial services, liability insurance, common area maintenance and property taxes.
While you may have nailed down every single expense in your commercial lease, the person responsible for putting together the monthly bill, espescially for larger landlords, probably won't review every tenants lease terms. This means that cost exclusion that you negotiated may not be reflected in your monthly rent.
It may sound strange, but you MAY NOT automatically have a right to audit your lease! You are going to want to make sure that you include a lease audit clause in your negotiations. This way you have the right to audit your landlords records every so often to make sure the details you so painstakingly negotiated are being accurately reflected in your bill.