There was the same discussion on this board a month ago. So here once more:
There is a vocabulary word "sela" meaning "rock" which has been used as a given name. There is another Hebrew word "selah", which appears in the book of Psalms. It probably marks the end of a paragraph, but its original meaning is not clear. One interpretation derives it from a word meaning "lift up"; this could refer either to the voices of the singers or else to their eyes. In the latter case it may ask the person or persons praying to lift up their eyes and repeat the last verses. According to another interpretation SELAH is derived from a word for "bow" or "pray", so maybe you were supposed to bow down in prayer at the end of the paragraph.
So SELA and SELAH may well be two different names and in fact they are. But people ususally don't cara muchabout Hs at the end of a name (cf. SARA/H, DEBORA/H) so the two might easily get mixed up.