That's a good one..
No I didn't use both seals, I removed the old one before installing the new one. I just rolled it to far down and it needs to be moved up a notch to seal. This is the first Volvo or insert/cartridge style filter I have ever changed. I am use to just putting a little oil around the seal and hand tighten, then 1/4 turn on normal filters.
I just wanted to make sure this was the correct way to do this. I decided to start changing my own oil (among other things) I guess about 15 years ago to save a little time & money. Be easy on me....I am new to the Volvo parts.