Scuba:From a business cost effective perspective, the numbers have to be worked out ahead of time. This can be complex or fairly simple, and there are no guarantee's from errors or market changes. The example you give appears to show you purchased too much compressor for your needs. You probably could have met your needs with a lesser but more cost effective compressor? Did you deduct resale price/value from your p/fill cost calculations?
Actually we limped along with a 5 cfm compressor which is pretty small. when it became clear that it wouldn't meet peak demand (like getting ready for a class or on a friday night) we added a bank system to spread the demand out. The extra cost of things like auto drains and shut offs were required because sometimes you interupted when the banks are filling unless you spend the night there...heck even then.
When I made those calculations I did not include resale value of the compressor. If I looked for a 2 year pay back on investment as I've always been required to do as an engineer I could never have made it fly even though you may not fully depreciate it in 2 years.
One of my main points was that a dive shop doesn't have a choice as to whether or not to have a fill station. With most manufacturers you are simply required to have one in order to sell their equipment. If you wanted gas sales to be a profit center (where we were) I don't think you couldn't justify thas cost of any compressor...which is why there are no "fill express" type places around here. Outside of what you use teaching the volume just isn't worth looking at. Unfortunately classes, at least Ow classes which is what you teach most of are also very often a loss leader. It all exists to sell equipment. If the shop must be cost competative with the businesses that are able to do aw3ay with instruction and a fill station the whole thing becomes just performing a service for the community out of the goodness of your heart.
I would have loved to sell equipment for a reasonable markup on the time it took me to order it. however, when you're not allowed to sell mail order or internet (which most manufacturers didn't allow at the time) you are destined to whatever volume the local market represents which puts you at a hege disadvantage when competing eith the likes of LP. The shop is saddled with all the restrictions, overhead and the lower volume. Admitedly, many manufacturers have started to allow internet sales but they still have the price restrictions. Enforcement may be spotty and inconsistant but trust me they do enforce it when it suits them.
Personally, I don't really sympothize much with the shops. They let the tail wag the dog. The manufacturers and agencies are clearly the archetects of the model and treat the shops like anything but a customer...more like an employee. Do you think it's coincedence that the co-founder of the largest agency was also VP of one of the largest manufacturers? Sales reps are pretty bold about walking into a shop with threats and demands for a bunch of non-diving jack azzes. Talk about parasites. they show up every year for just long enough to make you mad for the rest of the year and for that they get a commision on all your business! Kudos to the manufacturers who have dome away with their leeches...I mean sales reps. Boy could I tell some stories. LOL. Until the shops wise up and put their foot down, they won't be seeing much of me. You asked for it and you go it toyota!
The whole thing is backwards. Divers aren't treated like customers and even worse are regulated...by a store?...just go in and try to buy a rebuild kit for your reg. The manufacturers treat the shops like employees even though it's the shop who takes all the risk. Who is the customer here anyway? Of all, the divers, as a group, are even dummer because they usually swallow the whole thing.