I do if requested, but these days are not included in the quoted turnaround times, which are in business days. You can get your manuscript returned faster, though: For each day sooner you need your manuscript returned, add 25% to the standard price.
You submit a 6,000-word manuscript for a substantial edit on Thursday. The turnaround time for this project is 5 business days, which means a return the following Thursday. If you want that manuscript returned on Tuesday, add 50% to the quoted price.