Hi HLW,
You haven't mentioned breakfast, but I assume you normally have something to eat, in which case that won't be covered at all. As well as the glucose that ends up in your blood from the food you eat, your body also gets glucose that is produced by your liver. This can be produced in small amounts throughout the day, but by far the largest amount is produced during the night. This is the body's natural reaction to not getting any food for several hours - it assumes that it is being starved so produces the extra glucose to keep your energy levels up. This tends to peak from around 3am, so if you have all your metformin at, say, 1pm then during the night when your insulin needs some help it doesn't get any.
The other effect the metformin has is that it discourages the liver from over-producing glucose. If you have no metformin active at the time when most hepatic glucose gets produced then you are not getting the benefits from the metformin.
PS Actos is pioglitazone.