This is actually correct because all the cargo seats are ready for Firing from Vehicles feature. That means they are not regular seats but turrets config-wise, You may see it by the number of turrets of said vehicle. Does that explain the issue enough? If yes, please, close this issue, otherwise let me, please know.

Yes thank you for looking. Our program used for filling the helicopters uses the transport slot for loading. Now you have explained it, it makes perfect sense. Thank you for your response and keep up the great work