Problem with DBF Viewer PRO

I'm using DBF Viewer PRO to edit the players file, and when I do update multiple records, type in say -5 for Jump, it sets everyone's Jump rating to -5, instead of taking away just 5 from each player's rating...What's up wit dat?

At least you can get your DBF Pro to accept negative numbers. Every time I punch in a negative number or a positive value near 100, an error message comes up and says that its "out of range." What's up with that, and who can help me fix this problem?