They are pronounced the same in Japan, and only the Romaji is different..
Also, it's fairly common for people to use Western style for writing their names, so it's easier for non-Japanese to read/pronounce..
A lot of my students use "c" instead of "k" and "l" instead of "r" (Lisa, not Risa), and some just totally change it.. From "pei" to "pay" or "shou" to "show"..