Carvana vroom etc offer much lower than kbb, is it normal?

Hi, I have started leasing a bmw m340i from Dec 2019 and current it’s around 20 months of the 3 year lease. Due to covid, the mileage is only around 2000-3000 miles. KBB gives estimation of 56,000 usd for private party. However Carvana Vroom Carmax etc quote is around 45,000. Why is it much lower than KBB? Thanks in advance.

https://forum.leasehackr.com/t/carvana-vroom-etc-offer-much-lower-than-kbb-is-it-normal/374671