:Actually, no.  MosNUM clearly states that the original prefixes used in the articles are to remain.  "There is consensus that editors should not change prefixes from one style to the other".  You changed those over to kib's in March from their original KB notation.  How many edits you've done since then is irrelevant.  That passage was included in MOSNUM for specifically this reason.  If you insist on adding kib to the entry, then follow mosnum by using the "256 KB (KiB)" format.