My understanding is if I have 4 trigger words that I want in the same sentence, I would need to make the percentage 1.0
BUT, if I want each of the words to trigger a response by itself, I should set the percentage to .25 right?
If I have 10 different words, I should make the percentage 0.10?

Percentage of contained words is like:
N% of words from your word list should be in the message. If so, react, else ignore.

Examples:
"a", "b", "c", "d", "e". 5 "words" specified in configuration. If I want to react on at least one of them, for instance: aaaaaaa hi (since it contains "a"), I'll need 0.20% (1/5). If I want at least two "words" in the message, for instance: hey ahh ("e" and "a"), I'll need 2/5, so 0.40%.