Let's please start sharing information if you find anything to add to the chart. Together we can all make a big difference in helping the Tamagotchi community compile a complete chart.
I know that this thread is incredibly old and I'm sorry to raise the dead, but this is (and likely always will be) the top result on this topic, so it's pretty important for publicity to have this here.
A well-known Tamagotchi debugger on Tumblr named Curlour may have demystified a lot of the nuances of this model's toddler-to-teen evolution (and helped me figure out why the results from that growth log survey are so often contradicted by personal testimonials...). See the post here.
The reason becomes plain when you consider that the people in the survey were likely very good at raising Tamagotchis, and "shifting" to another family while growing to the teen stage generally requires poor (exactly 3 mental and 3 physical care misses) and yet not horrible care (which is an incredibly particular circumstance that's more likely to result in Universal for horrible care if you're not literally tracking care misses - a single mistake is enough to make the difference).
The survey results show exactly what we'd expect to see under this interpretation that, by coincidence as well as the nature of where the data was gathered, nobody gave poor but not horrible care:
Haruchi becomes Mame with anything but poor care, so all the results for Haruchi showed Mame
Puchitchi becomes Mame with perfect care, but Meme with anything other than perfect care, so the results for Puchitchi were almost 50/50 Mame and Meme
Mizutamatchi becomes Meme with anything but poor care, so all the results for Mizutamatchi showed Meme
Mohitamatchi becomes Meme with perfect care, but Kuchi with anything other than perfect care, so the results for Mohitamatchi were almost 50/50 Meme and Kuchi
