There have been data points since yesterday going both ways when applying for the CS Plat (by people who already had the vanilla Plat). Looks like while
the new restriction isn’t officially in the T&Cs for the CS and MS versions, presumably Amex’s popup algorithm is in full force.
I am a dp. Tried today for Schwab. Had vanilla closed a few months ago. Got denied on the phone after wasting a lot of time, tried online and got popup instantly