I've just switched to this calculator today after using another one for years because of the ability to calculate my lye solution masterbatch. While transferring all of my tried and true recipes I noticed almost all of my "longevity" numbers are low. Even on my harder bars.
The numbers should be just about the same, if the ingredients are the same. Can you post a recipe screenshot from both calculators, so I can take a look? BTW, ‘harder’ doesn’t mean always longevity unless it comes from solid oils- you could pound nails with an aged 100% olive oil bar, but it’ll melt fast in the shower. That is a generalization, but not always true.