Unfortunetly, that is the awful truth. I don't want even to remember how much those invested bitcoins cost me at the time. :-(
Also, take in consideration that I always reinvested all the payouts, so the total invested sum is higher than the actual BTC I had to invest.
If you're always reinvesting the payouts, you haven't really reached the breakeven point. You're just being credited with more paper slips promising hashing power that may or may not exist. You've only really reached profitability if you invested X in PBMining and now have X+Y in your wallet, where Y isn't negative.