> Since the cost was probably split between reduced profit and additional customer

As someone who prices and sells labor and material for a living, nobody ate increased tariffs. They were passed along to the ultimate consumer of the tariffed product. Everyone was facing the same tariffs so they’re all incentivized to pass the cost along, line iteming the tariffs on the invoice would make it abundantly clear. I passed along all increased costs with a note on my proposal that said “Any and all additional tariffs will be paid for by the customer.”