Did you actually go find a villager and do a request for them after I posted? Doing a request for a villager can be done multiple times to increase your score.
I don't know that it's a cap so much as a time thing. The same thing happened to me. I got from somewhere in the low teens to 89 percent on the first day and after a certain point nothing I did raised the percentage. I thought I had a glitch and went to the next morning and Isabelle congratulated me on reaching 100 percent approval.