I haven't been in sales or anything but I would assume being able to afford to hold the inventory is different as well. If they can afford to have 4 instruments totalling roughly $40-50k they must be doing something right.
Wholesale and retail prices are very different. Retail value of $50k is inventory value of ~$25-35k. And it presupposes that they have already paid for those instruments. They may have paid 10% to have inventory with the balance due at some time in the future (usually calculated to give a reasonable probability that the item has sold). So actual cash cost of that $50k may be as little as $2500. Still, they have a huge inventory. So, to keep their banker happy, they must have a good track record of turning the inventory and paying off the operating line.
I think that Cosmo is operating the business well.