I agree. Split the expenses with whatever seems logical.
Suppose your trip for Company A would be a flight in, hotel for the evening, interview day, then hotel for the next evening (you fly out the next morning). If you want to add another night, that would be paid by company B, and company B would cover food and expenses for that day.
If halfsies seems easiest and both companies are fine with it, then that just makes the receipt tracking easier.
