He space in the middle is the hyphen in the zip+4. You need to get rid of that. The postnet is typically the zip+4 and the delivery point code + a check digit.The check digit is based on Mod 10 algorithm. The value of the check digit is that when added to the sum of other digits in the barcode, results in a total that is multiple of 10. For example, the check digit for 91801 is 1 since 9+1+8+0+1+1=20 which is two times of 10.
If this is confusing you I advise you don't address your piece as it will not go where you want it to.
