Hey my man, every time a portion of coins is staked you will receive 20% of that staked amount. Now, keep in mind that you will recieve 20% annually. So a stake of 50,000 for a 20 day period should be about 555 Mintcoin if my math is right.
Exactly. People think they're receiving the amount of coins listed next to "Stake", but those are only the amount of coins that are currently mining for the PoS reward. With 20% reward over the first year, somewhere between one and two percent of the listed "Staking coins" will be rewarded per month. Everything is working as intended.