Since they share a health pool it's very advantageous to multi-dot during Heroic Morchok if you can pull it off. His stomp has a 20 yard range and your DoTs are 40 yards, so you have a 20 yard grace range to work with if your raid tanks them fairly close together. I wouldn't necessarily call it a "weird" strat, it certainly leads to a faster kill and is absolutely necessary for speed kills.
As for Zon'ozz, flails should be single targeted/bursted down immediately since they only have like 300K HP. The eyes should most definitely be multi-doted by moonkins since they have a fair amount of HP. Sounds like you're the one with the "weird strats"