SagaCoin's masternode reward is different from all other masternode coins, our masternode reward based on PoS. And it calculates winner similar to PoW did, so it is random but you will get your turn like mining did. So, sometimes you will not getting any reward in a few days, but sometimes you will win a couple of rewards in one day.
Current wallet supports multiple masternodes on one wallet instance, but we do not recommend it and we will modify code to limit one masternode per IP/instance in near future. The main reason for masternode is to reward your assistance to run a full node 24/7 to secure the SagaCoin network, but one machine with multiple masternode does not help to secure the network at all. Therefore if you insist to run multiple masternodes in same machine, please ensure you have multiple IP attached to the machine and run multiple wallet instances (one IP per instance) [Although this is not recommended too because it does not help much in securing the network.]