Once you're close to 17 syllables, count them with your accent as it's not 100% accurate to Western American dialect, as in this:
Chuck Norris Haiku # 20
Chuck Norris’ hand
is the only hand that can
beat a Royal Flush
Which only counted 15 syllables, because the British pronunciation is one syllable "rɔɪəl" while Americans break it into "rɔɪ ' əl."
It also didn't count Chuck Norris' as four syllables, just three. Probably because it was scared of Chuck Norris.