Welcome to the forum. I can't definitively speak for that individual Domme, but I would say it was part of the role play. Most clients want to hear that they are there to serve a Mistress's needs. That is kind of the point. I find it a bit odd that it threw you off in session.

From the perspective of a Domme, we walk a fine line of being "service tops" and true dominants in session. A Domme with longevity in the business is able to take your interests and wrap them into a scene where her needs are met.