I would expect someone who works in the industry to know that this website is extremely misleading. The process of airlines assigning airframes to routes is not deterministic and accurate data only exists within the airlines internal systems, which even then is subject to change right up to departure. The data you get in your feed that indicates airframe is just the most common model that has flown that route over the last 90 days.
Really wish people would stop building these websites.
On the note of high probability: we do use data sources that plug into the GDS booking systems for the flights, so it's not just a historical thing for this site specifically. While that once again doesn't give us a guarantee, it's likely better than relying on previous route aircraft stats.
https://www.consumerreports.org/consumerist/what-is-the-bait...