The system variable for the tool length offset differs depending what type of offset memory (A, B, or C), and how many offsets your control has.
Most of the recent Fanuc's I've seen are either B or C, both of which use #11003 for the Tool length Geometry for H3 and #10003 for the Wear. I would try
also, for backward compatability, you can use #2203 instead of #11003.
If you have over 200 offsets, you can get the values > 200 starting at #11201