Instead of thinking in just one 105oz lot from just one person doing a deal on any given day, take your mind for an exploration of HUNDREDS of those deals happening on one day (later, for a real experience, expand that to thousands) and then take that number to expand to 7 days, then 30, then 365.
Change the price paid every day - by $30/oz if you like (which rarely happens on a consistent basis) and remember to have some days that are up, some that are down (take the real gold price chart from the last few months to make this easier).
Take that total one year buy and divide it by 365 to get an AVERAGE price.
Every good business does this kind of thing - looking at the LONG TERM values, not just one deal from one person on any given day. It is called "looking at the big picture" for a reason - too much detail on too small a focus creates a lot of doubt.
Not sure what your interest is on this forum, but presuming you are 'Urban Mining' (gold from various ewaste products), it relates to the fact that there are millions of tons of waste out there and all you really need are a few good pieces. You have the belief that you will find them. And why? Because you know there are millions of tons of waste - i.e., you can see that big picture..... Take that scope when looking at Price Locking, you will get the idea.