This is the high end of the range. When you're abroad, you will pay according to the local rate, taking into account the source of your interpreter. If you hire her through a major hotel, expect to pay more. You may also be expected to pay travel expenses, food and lodging, depending on the circumstances. In addition, you may want to tip the interpreter, especially if she was hired through a hotel or agency.
Recommendations are important.
You never know who you'll get, especially if you're working in an unfamiliar city. Talk to the interpreter. Make sure the interpreter is fluent in both languages. This may seem elementary, but remember, your interpreter has to be able express himself or herself well in both languages. Have the interpreter orally translate written samples into both languages, in both directions.