If you don't want to mark up each expense by the same amount or percentage, you can mark up the expenses individually.
When you use this method to mark up an expense, QuickBooks does NOT post the difference between the original amount and the edited amount to your markup account. Instead, the entire amount posts to the account you use to track income from that type of reimbursed expense. To track markup income separately, you must use the “Markup amount or %” field to apply a single markup to all the expenses you select.
If you REDUCE the amount of an expense, QuickBooks assumes that you do not intend to charge your customer for the balance. You will not see the balance the next time you display the Choose Billable Time and Costs window for the customer.