Those numbers are meaningless. The ONLY numbers that matter are the ones published by FCA in the owner's manual... and that says the maximum tongue weight for vehicles without the factory tow package is 150#
Towing weights is always the LOWEST of the vehicle's numbers and the aftermarket hitch's numbers.
Trailer tongue weight and the weight of a hitch mounted accessory (i.e. bike rack) are two different things.
The trailer tongue weight is measured at the receiver ball which places the weight closer to the rear axle than where the weight of a fully loaded bike rack would be. This means the loaded bike rack may need to weigh less than the max rated tongue weight. But not necessarily.
The max tongue weight is an important consideration when towing a trailer
as it is related to overall stability of the tow vehicle and trailer combination. However, for an hitch mounted accessory, "tongue weight" is not a factor. It really comes down to how much weight can the suspension carry as well as the trailer hitch itself.
The max tongue weight is generally rated at 10% of the max trailer weight. This appears to be the case with the Pacifica. With respect to load on the hitch, this only means that the tongue weight
cannot exceed 150 pounds when towing a max trailer weight of 1500 pounds.
Given there is nothing that indicates the factory installed trailer package includes any suspension upgrades that increases the Pacifica's weight carrying capacity, a Pacifica without the factory trailer tow package should have the same hitch accessory weight carrying capacity as one with the factory trailer tow package.
The things to consider is that the hitch mounted accessory weight does not exceed the capacity of the hitch and the amount and location of the weight behind the vehicle does not affect vehicle stability.
Think about this, you would not want to place 700 pounds of something in the Pacifica behind the third row seats. The van can certainly haul 700 pounds with no problem but all that weight at the back will make the van unstable. This is similar for the hitch mounted accessory. It is about weight location not "tongue weight".