In my case, I only change my pricing once per year, and that time is right now. I ate the fuel increase from last year, and it kicked my butt, because I think fuel surcharges are the sign of the devil, but if an op has all of their advertising geared to a certain price, it's tough to change that price on the fly.
And, an op with a fuel surcharge can continue to offer $69 two tanks without feeling the need to indicate the fuel surcharge that makes the trip really $89. It's amazing how many sheep put up with this. Americans love to feel that they are getting a deal. If they wanted an all inclusive price, everyone would fly Southwest. The dive shop scam of mark it up 100% so they can give you a 20% discount makes everyone very happy.....
When you see $99 open water classes advertised, go on in and ask them what their book fee, instructor fee, pool fee, rental fee, open water fee, and all the other tacked on stuff will be. Personally, I'd rather be told that I'll be paying $450 for Open Water. Then I can make the decision based on all of the info, not some of it.