Nothing has been changed yet. For those who want to track performance of inventory kits, there is another problem though, that you should be aware of. There is a bug in computing inventory profitability, described in this bug report: Inventory Profit Margin report bug when Inventory Kits are sold. I suspect if you are trying to segregate income and expense by inventory kit you would also want to examine profitability by inventory kit. The bug report is about 6 months old, but @lubos has not addressed it yet.