We have weights for items in kgs so we need 4 decimal places, but every time we reinstall or big upgrade, it reverts back to 2. If we save items without remembering to change global options, we lose historical weight data for those items, as it rounds up/down to 2 decimal spaces. Making 4 the default shouldn't affect anyone, as people who use 2 won't lose their numbers. It only affects those using 4.