No some INDs are set to be as prototicall as they can,as to where you have to leave the cars to load/unload at a set time of your choice. These are called Proto Lars INDs Which has 79 difference products to load/unload.
The BI and BI2 industries will behave in the way you ask. You don't use load for the PL, just leave the car there for a while.
I have used many freightcars at industries without paying attention to whether they have the LARS designation or not, and have not had problems. The car does have to be configured to take whatever product is at that industry.