Amsoil AME 15w-40 / 1997 ford powerstroke 7.3

I have a 97 f-250 hd with the 7.3l 4-spd 4eod 3.55 screws, 195,000 miles. I just found a nice stash of amsoil ame 15w-40 at 6.00 a qt. Amsoil say 15,000 severe, 25,000 nornal duty. I was wondering what you guys say? I was continue running motorcraft filters, and change every 7,500 miles. Change the filter and add the make up oil, warm up and send a sample, that sound like a plan? thanks in advance for the help. ken