Say the first number is 12.52 and it prints kosher
Next number is 9.63 but the same cursor position would only overprint 12.5, and the result would appear to be 9.632. BUT if it was -9.63 it would be fine as it has the same number of characters. You can fix the first problem by printing the number and follow immediately by two blanks " ". Having two would fix 9.63 following -12.52. There are other ways of doing this that are smarter. If you assess the number before printing, you can lessen the risk of putting a blank over something you actually want to keep and also keep the decimal points lined up.