What is the flatness of the 10-A series of attenuators?

The flatness specification varies depending on the frequency. See table below:

10-A-MFN-1 (1dB)	+/-0.3dB to 1GHz	+/-0.5dB, for 1-4GHz
10-A-MFN-2 (2dB)	+/-0.3dB to 1GHz	+/-0.5dB, for 1-4GHz
10-A-MFN-3 (3dB)	+/-0.3dB to 1GHz	+/-0.5dB, for 1-4GHz
10-A-MFN-6 (6dB)	+/-0.4dB to 1GHz	+/-0.6dB, for 1-4GHz
10-A-MFN-10 (10dB)	+/-0.4dB to 1GHz	+/-0.8dB, for 1-4GHz
10-A-MFN-30 (20dB)	+/-0.5dB to 1GHz	+/-1.0dB, for 1-4GHz
10-A-MFN-30 (30dB)	+/-0.8dB to 1GHz	+/-1.3dB, for 1-4GHz