Hola William,

I am afraid there is a limit to what the system can do in terms of spelling mistakes. The system can't recognise if a student is spelling a word in Spanish wrong because of his/her fast typing and accidentally typing the wrong letter, or that mistake is to do with the student not really knowing what the right spelling is for a Spanish word (which needs to be learned). 

The system doesn't penalise the use of a capital letter or lower case, for example, and depending on the test, written accents are not penalised or just 5%. 

Saludos,

Inma