Given the backlog at Hong Kong airport, don't be surprised if UPS's May 27 date slips by two or three days.
As you can see, all of these Max orders that were delivered May 18, 19 and 20 had some slippage from UPS's original estimated date:
@BenGieCruz (US), ordered March 24: Delivered May 18! (delivery originally scheduled for May 16)
@cinder (US), March 30: Delivered May 20! (originally May 18)
@evilhsoj (US), March 31: Delivered May 18! (originally May 16)
My Order (US), April 1: Delivered May 20! (originally May 18)
@placerights09 (UK), April 8: Delivered May 19! (originally May 16, then May 18)
@michaelm_photo (US), April 15: Delivered May 20! (originally May 19, then May 23)