I am testing my site in Paypal Sandbox. By viewing commission (wp admin > woocommerce > commission), it looks like the shipping funds are being allocated to the vendor, not the admin. But in the admin’s paypal account it is happening what I said earlier. Admin always keeps the shipping money. (I can post screenshots of the paypal log later)
I paying my test vendors using NOW (mass payment) for these tests but in the future I’ll use monthly schedule.