I was able to fix this using my renderer but... I fixed that using floating point numbers and the type in the C code is int. So I think the upm will have to be increased from 20 to 2000.    
I was able to fix this using my renderer but... I fixed that using floating point numbers and the type in the C code is int.
So I think the upm will have to be increased from 20 to 2000.