I am with a Volunteer Fire Dept that has not been inspected by ISO in 20 years well to make a long story short they called and here we go. One of my first questions is can you get Engine Company credit and Service Company credit for one truck or do you have to pick one or the other when it comes to ISO?
An apparatus can only be counted once. So to answer your question it is either an Engine or a Service but not both. The good news is alot has changed in 20 years so you may be in a good position to receive a better ISO rating, but then agian maybe not.