I just wanted to note that my most recent biz plat sign up bonus posted with $10,002 of the $15k spend requirement being fed tax payments (I always do payments of $5001 to trigger the 1.5 MR multiplier on the charge). I usually try to make the $15,001'th dollar be a charge of something else, which in this case was my March apartment rent. I'd chalk most of these worries to Amex's known/occasional sign up posting delays.