doesn't all this change considerably depending on our opponents calling ranges?

am I missing something?

Can I ask a really stupid question?
How do you calculate the percentage that someone will fold?

I've only briefly skimmed the charts but they are based on average calling ranges that the poster of the charts has collected over a large sample of tourneys aren't they? If you have more specific information on your actual opponents its common sense that you can make better +eV decisions then following a chart based on averages.

The charts also don't take into account a lot of variables that mess up the math.