Yup, that cleansing box causes loads of confusion for most soapers when they first start. Unless you are a grease monkey, landscaper, or person with a similar sweaty job, you probably want to max out at 12-15 if possible. My sweet spot is 10; my DH likes 10-15. He starts to get scaly if we go above 15.
ETA: Just saw your other question. I actual render my own lard most of the time, because I get it very cheaply from a local custom butcher. I add ROE to keep it fresh, just in case my rendering job wasn't perfect (and it probably wasn't).
I've previously purchased the Armour lard from Walmart. It has those additives and soaps just fine. But I just learned Smart Foodservice is right down the road from me. They sell a 48lb bucket of Viva lard for $51. It will take me a LONG time to go through that much lard, but since it doesn't go bad, I'm thrilled to find it at that price. That brand has BHA and citric acid in it, but again, those don't affect how it soaps.
Since you are just starting out, a smaller tub of Armour or SnowFlake from Walmart or the grocery store is a good way to start. If you decide you like it, then it will be time to make those bulk buys.
Oh, and I forgot to mention another benefit of lard is that it makes a very light-colored batter. Some oils (EVOO, Avo), will color your batter greenish. Fine for St. Paddy's Day, not so much for Valentine's Day.