No, but I don't know the exact differences. It may be as simple as the individual applications with no actual changes in the filters.
The Amsoil website says the following:
"When used in conjunction with AMSOIL synthetic motor oils, AMSOIL Ea Oil Filters are guaranteed for extended service life:
• Ea Filters designated with product code Ea15K are recommended for 15,000 miles/one year, whichever comes first, in normal or severe service.
• Ea Filters designated with product code EaO are recommended for 25,000 miles/one year, whichever comes first, in normal service or 15,000 miles/one year, whichever comes first, in severe service."
Pablo is one of our resident Amsoil dealers. He may chime in here or you can find him somewhere on the forum and ask direct. Please share what you learn if you do it PM. I could speculate and have some ideas but all that might do is project the wrong info.