sc_decode usages

Please let me know if I am using this macro incorrectly.
On a single record form, on Validate event, I am encoding a field
{officer_num} = sc_encode({officer_num}) ;

MySQL database correctly gets updated with an encoded value.

On Load event :
{officer_num} = sc_decode({officer_num}) ;

The value does not display correctly on the form. It just displays the first 2 characters of the decoded value.

It seems correct to me.

What is the original value? What is the value being saved in database? And what is the displayed value on the form?