IIRC - there was a discussion in connection with how BARAK obama sr was always shown as BARACK OBAMA both in 'Dreams' and in articles written about him in Hawaii - yet when he returned to Kenya he wrote the above article (which is reported as having annoyed Kenyatta) he wrote his name as BARAK - dropping the 'c'
The name BARAK is closer to the phonetic spelling of the arabic. The additional 'c' may have been how the teachers enrolled him in the christian school he attended.
After independance in 1963, as a Kenyan, he would have been quick to discard anything to do with a spelling that might be interpreted as a 'colonial hangover' -
However, Obama Two was stuck with the english version. In 1964 any self-serving documentation that had been raised to claim obama sr as the father carried forward the name BARACK. (imho)