Dude, a tip that might ease some frustration with parallels is to search Hoskins, click filters>card numbers, then select PP-16. In the results, hopefully this is the only one that's SN250. Not as easy if it's not an SN parallel, but I do it that way a lot. Of course I'm colorblind, so I can't just look at a card and know what color it is.
I'm going to reevaluate how I collect after the new year. It's just getting way too expensive for the new stuff. Sometimes I just want to buy a pack, not a whole box or even blaster.