Thanks for checking. I am including a screen name in B9. (Same results for my screen name with or without including it in cell B9)
I get a similar problem for any user. favorites/list for @mhawksey, for example, gives 199 tweets, going back to a favorite from October 19, 2016. I’ve tried this on multiple computers and drive accounts — always returns exact same number of favorited tweets for a given screen name.