Last time we went to the BVI for a week in a 40-foot Cat (2 years ago) it was $400 for 8 people for a week.
We almost always clear in at Jost. Very nice folk there.
However, no reason not to clear in at Soapers if you have a need to go there.
BTW, we clear in and out of the BVI at the same time, which saves you a departure stop. Just leave on the day you plan to, and all is good.