I have another idea, but thanks to the post derailers I will also need to repost my previous advice. They seem to enjoy burying them with personal attacks and misquoted attributions. A review of bunnykins post is also useful
Hopefully I can give you this new advice without being accused of telling everyone what to do. So try this:
Collect a list of the price leaders (e.g. hostgator, godaddy, 1and1) and make a spreadsheet of their plan resources and prices. Compute some averages and other stats. Settle on some price points. Then check your costs. If they are out of whack with the prices you just came up with you can either change the price, change the costs, a combination of the two, or just don't offer that plan.
I believe with this and what I have posted earlier -- done so without knowing any cost -- can get you a good starting point. I now repost what I posted earlier to help inoculate me against those that say this should not be done and misquote me to score brownie points with the general public:
Op doesn't have to post costs to get advice. Guide should be the market, not your costs. If your costs are not in line with market prices, do something about costs, not the price. If a host needs to charge 3x more than anyone else to cover costs and follows this advice, he will pay the highest price: failure. In some scenarios, operating at a loss is a better option.
If the above isn't used against me as a claim that
you don't need to know your costs, instead of
we not knowing, I won't be surprised. Context switching by the peanut gallery here isn't new.
When you were told what to do by the person that accused me of telling everyone what to do, i.e., that you must use the same formula for multi-tiered limited plans as you so for unlimited plans, I offered this advice:
Consider offering a single limited plan, but large enough so that the resources offered are much higher than what can be used by a personal or small biz web site in a shared hosting environment (per tos). Here you can offer what is effectively an "unlimited plan" while at the same time provide the limits required by some forums. For example offer a single 25 GB plan priced at your competition's 5 GB plan price or your original unlimited price -- operating under the assumption that virtually all sites will not go over 5gb anyway. (of course you may have to "oversell" to do that)
This will at least allow you to use the same formula.
Like you said, your calculations to predict PL will change with the multi-tiered approach since you will have a mix of products and pricing with an unknown percentage of each contributing to total sales. Information about these percentages by the others here, rather than insisting to know your costs, would be most helpful here.
Also consider bunnykins concrete and similar advice from a consumer's prespecive:
http://www.hostingdiscussion.com/we...red-hosting-price-suggestions.html#post168011
In short, view the landscape and then turn inward.