Dear XXXXXXXXX -
I would record the expense in the cost of goods sold section. That way if you record the reimbursement as income it will be net out against gross profit. If you net the reimbursement against cost, it will be zero w/in cost of goods sold.
Certified Public Accountant (CPA)
CPA, Over 29 yrs experience w/individuals and small businesses. Masters in Tax, Divorce Specialist
If the installation was part of the contract, I would definitely include the amounts in cost of goods sold. Even if it wasn't think it is a good place for the cost. As an alternative, in other expenses, you could create an account called unreimbured client expenses.