That's fine for now, i'll judge your pool only by profits made, but your reasonment here have a great bias: the variable here is the fees income, not the server cost. If your pools perform better than expected you could set LOWER fees, while in "bad days" you could need HIGHER fees to mantain the servers.
If you otherwise decided to set variable fees in the way you said for marketing reason it's more understandable. But, either ways, i think you should asap declare how much the fees actually are. No way to test if you're saying the truth since we don't know what coin we're mining so we can't do a accurate estimate of the expected profit (just some guesses based on net difficulty), but knowing how much fees you're paying make the user much more confortable.
PS: me too think that multipool owners are at most cheaters or incompetent. Never find a decent multipool till now (i.e. better than mining doge or whatever on a single pool with ~1%fees, switching coin every 1/2days), i really hope that yours is different
Thanks for understanding. The progressive fee and operating costs have nothing in common. Progressive fee is my attempt at a new model that people will hopefully find attractive as it makes the hit smaller on bad days. You might call it marketing.
Unknown costs. I've just never ran a pool before so I don't know how powerful servers I'll need for this once more people join. I have been beta testing this software for a long time, but it was with 20 users only. I have no idea how it scales and what my costs will be.
What I know is that I was really surprised on how much resources are taken by coin wallets. A single coin or five coins are fine, but when you install and run wallets for dozens of coins, it suddenly starts requiring a very powerful server with lot of RAM, SSD disks (because dozens of coins are constantly writing new blocks into disks) and fast networking. This is what I discovered during my closed beta and I needed to upgrade my wallets server to a much more expensive because of that. This one probably won't change with increasing number of users, but I just want to check what other cost-related surprises are waiting for me before I commit to final fees. While the pool works reliably, this is a work in progress and I'm still testing and tweaking things.