I'm not sure what you're referring to by 1:1, but all my expenses are paid in full by my clients, so long as I am billing within their guidelines (that said, I stay within the guidelines 99.9% of the time so as not to have unbillable expenses). Most client's guidelines are within reason, and most know to allow for higher cost in certain areas.

If your clients are increasing expenses by giving you last-minute marching orders, then they need to be prepared to pay the higher cost involved.

In my field, you set your hourly rate. Your hourly rate is in no way connected to expenses.

Hope that helps.