Compare the inputs
For 25 April 1990, the day alone gives 2+5=7. The full date gives 1+9+9+0+4+2+5=30, then 3. The month and day together give 4+2+5=11. A different set of digits naturally produces a different result.
Japanese naming conventions
Some Japanese explanations call the day-based number shukumei-su, the full-date number unmei-su, and the month-day number shimei-su. These are not universal definitions. The primary result on this site uses the full date and is called the life path number in English.
What about the soul number?
Soul number can refer to a birthday calculation in some explanations and a name-vowel calculation in others. A calculator that never asks for a name cannot calculate a name-based number. Check the inputs and the formula rather than relying on the label.
Interpreting the word mission
Shimei can be translated as mission, but that label does not impose a duty. The themes are prompts to consider, rather than instructions about which family or career choices you must make.