I had to pay a 5% late penalty when I went to pay my taxes. I thought I should warn others about this. Though Texas law is clear that the tax on a vehicle purchased in another state is due on the 20th working day after the date the vehicle is brought into Texas (Texas Transportation Code 152.041(d)), in practice the tax office policy is to only accept the date on the MPVA. I tried at both the state and county level to get this fixed, but without success. I promptly signed and returned the purchase agreement with cash payment. This turned out to be a mistake because the MPVA was dated well before my delivery date. I would suggest holding off on payment until you take delivery so as to avoid this problem.