Reduce prescription?

I have been taking indo metformin 500 (2 tabs a day) for 13 days and my fasting bg has dropped to 4.8. Should I reduce the medication to 1 tab a day?

mmol/L Date Time
8.8 19/10/2008 08:46 AM
8.2 26/10/2008 08:28 AM
7.2 27/10/2008 06:06 AM
7.7 28/10/2008 06:02 AM
6.9 29/10/2008 06:09 AM
6.6 30/10/2008 06:02 AM
7.3 31/10/2008 06:32 AM
6.1 01/11/2008 07:54 AM
6.2 02/11/2008 08:08 AM
6.3 04/11/2008 06:14 AM
4.8 06/11/2008 06:12 AM
4.8 07/11/2008 06:13 AM