Why can't you split the vehicle between two Sch C? You enter the vehicle twice; asset entry for each biz. You enter total expenses for the vehicle on each and let the program allocate when you put in the biz miles per each biz. So van is driven 40000 miles total, 10000 for one biz, 20000 for the other and 10000 personal. one biz gets half usage, the other gets a quarter, and one quarter is personal. I've done this for my car which is used for rentals as well as my biz.