Ethiopian Calendar

That's a tough question to answer.

I practice Pythagorean numerology with the Gregorian calendar, and have no experience doing numerology calculations with other calendars.

A guess is that the calendar that was used when your birth name and date was first recorded is the one that's the most applicable. However, both dates may affect your reading.

My recommendation is to do parallel readings, one for each birth date. Compare the two life path interpretations. Then compare the pinnacle cycle, life period cycle, and personal year interpretations. Determine which are the most accurate to understand which date has the most or nearly all the influence. If each has significant accuracy, then both dates have an influence.

When you do the parallel readings, the second life period cycle will calculate to identical results for both birth dates. But every other chart position that uses the birth date in its calculations will be different.