Fairness in hextech mystery champion shards

The hextech system has roughly been in league of almost 1 year now as a frequent user of it (not intrested in anymore champions currently) ive noticed over the year of just using it, it hasnt always been "fair". Specifically the mystery champ shard that cost 1700ip, I have opened probably around 50 of these just using ip and little rp and ive noticed your chances to get a champ under 3150 or something you already own are extremely higher than getting a 6300 champion or something you dont own. Obvious fix is just save for whatever expensive champ you down own already and buy it with ip but you have to grind game after game for a long while to do that something I doubt a lot of casual players have time for (irrelevant but I am not a casual player). Im not sure if this was done intentionally but I think it would encourage people to buy these more and make the hextech system more healthy. A few experiences ive had with are like getting soraka almost 4 times in a row despite having already owned her and her being 450, getting malphite like 3 times in a row, stuff like that. If the system was just 100% random I think that would be better I would find it hard to believe im just this unlucky.