How can AA identify returning visits from 90 days ago if Adobe's first part cookies are limited to 7-day expiry

In a recent analysis around new vs repeat visits my team was doing for our e-commerce site, we noticed that we could tie an order from today to a visitor who had previous visits up to 90 days ago. This is without any on-site authentication data, this is strictly visitors who have not made an account on our site, but placed an order as a guest today, and had previous visits 90 days ago. 

According to this documentation, Adobe’s first-party cookies are limited to a 7-day expiry or, for click-throughs that Apple determines are coming from trackers, a 24-hour expiry. With a 7-day expiry, if a user visits your site and returns within seven days, then the cookie’s expiration date is extended by another seven days. However, if a user visits your site and returns in eight days, then they are treated as a new user on the second visit.

I have also read here that on Chrome browser for example, cookies can last up to 400 days before expiring, and wondering if this is the reason. Although this would contradict the Adobe cookie limitations mentioned above.

For context, the metric used to pull this data is the default out-of-box revenue metric, with the "use non-default attribution model" setting on, and a 90 day lookback window selected.

Any insights around this would be appreciated!