Has anyone ACTUALLY bred Zumi or Zero dragon?

I have been trying to breed these 2 dragons for like 2 weeks now and I’m starting to think its impossible lol. If I’m not wrong, the breeding combos are:

Zero= PERMAFROST + SNOWPOCALYPSE Zumi= SNOWBALL + KETU

I would get, to an extent, not getting Zero for a while given its a 1.9% breeding chance with 77 possible offspring but Zumi is a whopping 4.2% breeding chance with only 17 possible offspring. Even my dragons for both combos are all level 16, so if anyone knows something I’m doing wrong or something that could help PLEASE let me know🙏🏼