Hi Ludwig,
I completely agree with you in regard to the GL parameter 'delete close-of-year-transaction during transfer'.
However I was talking about the undo parameter when you run a year end close. In older versions this was called Reset I believe.

The GL parameter does not affect this, just to be sure I tested it in a Contoso company (10.0.4 / PU28).
Tests with parameter set to Yes:
Transactions Before:

Transactions after running the job with Undo set to yes:

Transactions after running the job with the Undo set to no:

After this I changed the GL parameter back to No, and performing the Undo gave the same result:

Best regards,
Ties Philippi