Question about Philips Hue Hue Lightstrips BT + extension

In the specifications of this product it says that this strip with extension has 1600 lumens. But if I now look at the same product base 2m, this also has 1600 lumens and the extension 1m 950 lumens. Shouldn't the number of lumens be added together in the specifications of the set? In other words, the set should have a lumen count of 1600 + 950 = 2550 - or not?