St. Patrick's Mystery Boxes: purchase or not?

Okay so I sold all my KEM in storage. Got over $1M back. Not really sold on KEM farming but bought 20 to try it out and turned on the collider. That should yield somewhere between 500k and 600k xp. My multiplier is 597.75 without hidden (so that would be a bit more than 800 total) 2000 xp × 20 kem × (800% multiplier + 500% collider) = 520k xp which means 2 rounds (8 hrs) per day (1M xp needed for bonuts) to recoup the 10-day collier cost. Any additional rounds I manage each day is the icing on donuts... (yes I love when math and food come together). Will see how I feel after 10 days.

EDIT: My math is wayyyyy off. Please see my later postings on next page.