I sent an EMS last week to US. Posted afternoon 16 Aug. Processed thru Suvarnabhumi 17 Aug, 1:36 pm. Processed at ISC Chicago 21 Aug, 11:40 am. Inbound Out of customs 23 Aug. ETC. EMS, still not delivered, but... on it way.
Posted a 1st class document Tuesday, 23 Aug 11:42, Processed thru Suvarnabhumi 24 Aug, 12:36 pm. ......
I don't use the Thai post to track when I send to US. I use https://tools.usps.com/go/TrackConfirmAction_input