Different types of sales
(A)    Invent, specific offer for sale, performance: Bar at time of offer
(B)    Invent, general offer for sale, performance: Bar at time of performance since invention was not relied upon for sale. No profiting off of it and easier to administer.
? However: Invention makes it cheaper to make general offer, then the bar might be raised
earlier to time of offer.
(C)    General offer for sale, invent, performance: No good answer.
(1)    Pfaff: Moment of invention raises bar, that item is now subject of a commercial offer.
(2)    However, a general offer for sale might not be fairly read as a “commercial offer for sale” since the inventor isn’t selling the exact invention. Thus maybe it should be at performance.
(D)    Specific offer for sale, invent, performance: Pfaff, bar raised at time of offer.