Looking at the Sterephile simulated speaker load FR/Impedance diagram, you can see the lowest impedance is 6 ohm, vs the 2.6 ohm of the Focal. So their simulated speakers isn't as difficult to drive. WIth the Focal, the AR amp would have a higher variation, and you can figure out by how much using the equations from the Benchmark article.
Damping Factor - Interesting article
Benchmark Media published interesting article on Damping Factor. I already knew that it does not make much difference for the damping of the membrane, but low output impedance is necessary to drive changing impedance ot the speaker (ideal voltage source). According to this article DF=100 produces about 0.5dB variations typically, while DF=200 reduces it to 0.1dB. DF above 200 is inaudible.
https://benchmarkmedia.com/blogs/application_notes/audio-myth-damping-factor-isnt-much-of-a-factor?omnisendAttributionID=email_campaign_5eda3b728a48f72deaf34bf2&omnisendContactID=5cf9266b15b61cc5a2a4dee7&utm_campaign=campaign%3A+AUDIO+MYTH+-+%22DAMPING+FACTOR+ISN%27T+MUCH+OF+A+FACTOR%22+%285eda3b728a48f72deaf34bf2%29&utm_medium=email&utm_source=omnisend
https://benchmarkmedia.com/blogs/application_notes/audio-myth-damping-factor-isnt-much-of-a-factor?omnisendAttributionID=email_campaign_5eda3b728a48f72deaf34bf2&omnisendContactID=5cf9266b15b61cc5a2a4dee7&utm_campaign=campaign%3A+AUDIO+MYTH+-+%22DAMPING+FACTOR+ISN%27T+MUCH+OF+A+FACTOR%22+%285eda3b728a48f72deaf34bf2%29&utm_medium=email&utm_source=omnisend