When i change the multiplier it adds to stack size in data file. When I first loaded the new plugin I had deleted old file and data. The stack size for stones is 3k when its 1k and every time i change the multiplier it adds it to stack size.

it says it will do that in the "Quick Important Notes" documentation.

I'm sorry, I'm having trouble understanding what you mean. The plugin doesn't modify entries in the data file, it creates entries when new items are detected, so the plugin won't modify the data file. The only way the data file changes is if you modify it. If you set "CustomStackSize" it'll use that stack limit multiplied by the defined multipliers in the configuration.

If you must have a multiplier, you'll need to set the CustomStackSize to a fraction of that multiplier. Or alternatively you can define the item in the config under "IndividualItemStackHardLimits" which overrides the data file setting as well as multipliers setting it exactly to that limit.

If you'd like functionality added or changed, let me know.