No one really knows all the criteria that the algorithm considers (it's all 100% automated and even customer service doesn't know exactly what all goes into it) and no one will be able to give you the definitive answer.
However, I can tell you that your total sales volume is not the only thing that is considered when calculating your potential loan amounts. We do know that it also considers trends/spikes/dips, and it places particular emphasis on the most recent 90 days of your sales history. There are most certainly other factors as well, though.
At the end of the day, however, it is often seemingly random and again, no one really knows. I've had steady increases in sales before and basically checked all the known boxes if you will, and had the next loan be significantly lower. Then, with little to no change in situation, I've had the next loan after that be almost doubled in amount. I also know that PWC will supposedly loan up to 35% of your previous year's sales volume, but even after multiple loans and a perfect history, we've never been loaned anywhere remotely close to that limit.
It truly does feel entirely random at times. I know that's not entirely helpful to you, but that's the reality of it.
