IMHO - as "interesting" as it may seem to see someone create and use their own scoring system - I think its great to see someone really into the hobby. So in general I think its good. On the other hand, I wouldn't put value into anyone else's scoring system - private or commercial - unless it was inline with my own personal grading system of notes.
I collect graded coins myself. And as anyone that does collect coins a tried and true saying is "buy the coin not the holder". I belive with the advent of third party grading... it will be even moreso with banknote collecting... only because notes are more prone to various forms of damage and wear that is debatable than wear on a coin.
Again, imho...