This is a more complex solution than the one I have already outlined above, and is a non-standard use of BIP39. The maximum allowable entropy for BIP39 is 256 bits. By padding a compressed public key with 6 additional zeroes, you are now using a 288 bit number. Your process also calculates and appends a non-standard 9 bit checksum, before encoding the whole thing in 27 words. The 27 words you end up with are identical to the 24 words I outlined in my process, but with 3 extra and unnecessary words appended to the end.

A 264 bit compressed public key encodes exactly in to 24 words. No need to overcomplicate things unless you really want a checksum for whatever reason.