The point is that, if each of the prospective buyers has cash, they can have an auction and whoever is willing to pay more for it gets the unit of product, assuming they bid high enough to at least exceed the price at which the supplier offers the unit.

If all you have is a redeemable scrip with a face value of 1 unit, you can't have an auction.

I don't know whether you can even have an auction if there is some redeemable unit-valued scrip left outstanding because if I hold the unit I can always outbid everyone else (if you bid €10 I can bid €11 and then pay with one unit of scrip rather than cash) but if there are two units of scrip outstanding there can be no winning bid.

I guess you can always do it pro-rata. You specify that any scrip presented on the third friday of the month before close of business will be redeemed pro-rata at auction before any cash bids. You also specify that you'll be putting up for auction no less than a set amount of units of production (in my example, 10 per month).

En un viejo país ineficiente, algo así como España entre dos guerras civiles, poseer una casa y poca hacienda y memoria ninguna. -- Gil de Biedma