My steward got in touch with the DR and apparently the trays ARE considered parcels if it's a "Firm Direct" drop point. If it's not, then the letters have to be counted under column 1. My steward think it's not a firm direct drop point but I'm not so sure. She is going to try and find out if it is or not.
All I could find about "Firm Direct" is the definition on the USPS website which says that it's "Mail to a company or business that, because of volume, justifies a separation on the primary or secondary sortation of incoming mail. The mail is generally tied in bundles and delivered intact to the business delivery address."
All their flats, raw mail and packages have to be sorted and separated by me. The mail in trays isn't tied in bundles either. Is that still considered firm direct? I have no idea. I've heard my supervisor use the term "Firm Direct" before, though, when referring to the park on my route. Guess I'll find out soon.