I just tried this.

1) I logged in to the withdraw server, and saw my outstanding balance:



2) I clicked to "instantly" transfer my balance to the new MP. It told me my balance had been migrated:



3) I checked on the new MP and found that my balance was still empty:



So what's the deal? Is the transfer function broken, or just a bit slower than advertised?

I did see an option to withdraw on-chain but the fee is excessive. 500 bits for a transaction when the mempool is empty and transactions cost around 5 to 10 bits per output?