check out feinternational.com (OP mentioned them as well). I've been subscribed to their "Buyers list" for over a year and I've seen many nice saas businesses listed.
https://feinternational.com/blog/saas-metrics-how-to-value-s...
So while 3-4x is normal (really 3-5x depending on the industry) the numbers on FEI tend to be a tad high but not unreasonably so.