The program is not intended for playing Video Poker but shows an optimal cards discard strategy for many types of Video Poker games with different payout. The free version supports "Jacks or Better" only. In order to be able to deal with any payout table the program plays about a million random game with all of possible discard and chooses the most profitable one. An expected value which the program counts could be a little bit different (about 0.5% for a million tries) from the mathematically precise value. So when there are two very close by expected value discards you could get one of two the best ones. Practically the discard advise you are getting is so close to the mathematically precise strategy then the difference can be neglected.