I hope Pyronis doesn't mind me sharing this. If so, I will take the link down.
http://stormhavenserver.com/download...or-Install.zip
I just installed it and tested it out and it seemed to work fine still. Nice little program. You just install it using either one of the install files (exe or msi), and then when you run it, it has you put in the db info so it can pull from the blobs.
Using the tool is pretty straight forward. Just load in the characters and wait for it to pull all of the data (takes a few minutes for large DBs). You can do individual players, or all at once. You can see current plat values, and edit them by dividing/multiplying/adding/subtracting. I would strongly suggest you first try this on just 1 character and make sure it works before doing any more than that. I also recommend doing a DB backup before you run this for all of your players of course.
He also shared the source code with me, but I won't share that here unless he gives the ok.