Hi Subhash,
Looks like the issue is due to the timezone difference in ECC and APO.
Most of the cases the timezone which is used in APO is UTC Timestamp, you will have to check the timezone mainatined in ECC and whether ATP Buckets are configured correctly.
The order time is getting scheduled backwards to UTC due to which it is falling 1 DAY less.
This can be checked by adding the local time zone difference with the UTCtime to the sales order schedule line shipping data.
For eg: if the you are in UTC+5:30 timezone, maintain the shedule line shipping data time zones as 05:30:00 instead of 00:00:00.
Let me know incase you are not able to resolve with this.
Regards
Ajith Kamal TN