Coins go short from time to time. The only coins guaranteed for a payout are BTC and LTC. However LTC can go short from time to time but the pool owner manually refills the LTC supply daily at least.
Ok, I can discard warning and keep mining with LTC payout ?
Yes you can, as he told me he only does that for LTC. So you don't need to worry about that =)
Idk why, but I'm using the miner now for nearly a whole week. And I never reached the daily estimated profit, it has always been way less.
most of these estimates take historical data, and/or use current luck factor :/ their a rough estimate at best

a pool could hit a few lucky blocks and your daily profit would shoot up, dosent mean the pool will CONTINUE to hit fast blocks :/
ive never made what a calculator says either, always +/- 10-20%
Well for me its mostly like - 50/60%. But never +/- 10-20%, I mean that would be great but not reachable for me at any point.