Yes, I meant Phyton, and have corrected it. Sorry.
Once in solution, the form of the copper ion is likely the same, so I cannot see one product being more easily absorbed than any other. Phyton has always made that claim, and at one time claimed it had an ingredient making it so, but as that would make it an active ingredient that had to be disclosed on the label, they have since dropped that statement
Copper is readily absorbed by plants both through the roots and through leaves that are not well-guarded by waxy cuticle layers, which is probably the reason folks warn to avoid spraying “thin-leaved” orchids like coelogyne and gongora, as they would absorb it so well it would be phytotoxic. It is then a quite effective system fungicide and bactericide.