That specs sheet is wrong.
15.7 kHz ----> 240p / 480i @ 60 Hz, 288p / 576i @ 50 Hz
(any monitor supporting 15.7 kHz will support 240p / 480i)
The sheet also specifies 15.1 kHz instead 15.7 which is also wrong.
Probably the confusion comes from the CGA having 200-line modes, but those were 70 Hz instead of 60 Hz.