Is this post of any help at all.
I've had similar problems in the cloud. The application code used SYSDATE throughout and was getting the wrong times back as the cloud servers were all Oracle Linux with the UTC timezone. We were not allowed to change that.
If I remember correctly, we changed the code to use CURRENT_DATE instead.
SYSDATE returns the server time with apparently no adjustments for the session timezone. In our case, we got UTC from the server. Our sessions were in BST and thus an hour out.
CURRENT_DATE returns the server date and time adjusted to the sessions timezone.
If SQLPlus gives different results from Toad, check your session timezone for each and compare.
Select SESSION TIME ZONE, DBTIMEZONE
from dual;
HTH
Cheers,
Norm. [TeamT]