Deductions & credits

If you put in 7500.00 it will calculate a 1875.00 credit. I thought it was interesting when I put my cars info in and Turbotax initially gave me a 7500.00 but then I had to manually put in 1875.00 and I got that credit but now today I go in and I only got a 469.00 credit. I will also delete the cookies and start over.