@winzou @pjedrzejewski I am now in a dilemma. 

https://gist.github.com/umpirsky/8d76a7c064844b35081f

For payments we did it like in `InventoryUnitController1`, but in this PR @winzou insisted to do it like in checkout `InventoryUnitController2`. I am confused and dont know which way to go. Please help. Personally, I am more for `InventoryUnitController2`.