The phrase "added a qualification" is correct and usable in written English.
You can use it when you want to indicate that someone has included a condition or limitation to a statement or argument.
Example: "After reviewing the proposal, she added a qualification to clarify her position on the budget."
Alternatives: "included a stipulation" or "made a caveat".
"Oakes argued that 'fighting terrorism is obviously important' but added a qualification: 'accountability journalism is important too'," the editorial said.
But he added a qualification that went to the heart of the power that Mr. Murdoch has amassed through his newspaper and television holdings, which command an imposing share of the British market.
Shankara, an outstanding nondualistic Vedantist and advocate of a spiritual view of life, began with the Neoplatonic alternative but added a qualification that turned his view into what was later called acosmic pantheism.
In Grutter v. Bollinger, the first Supreme Court decision upholding the constitutionality of affirmative action in higher education, Justice Sandra Day O'Connor added a qualification unseen in any other major constitutional interpretation.
Then he added a qualification: "It is not, I think, humanly possible for any reporter to be completely objective, for we are all to some degree prisoners of our education, travel, reading — the sum total of our experience".
"You don't need a printer in your car computer," he explained and paused a second, perhaps imagining what he might do with a printer in the back seat, and then added a qualification to the next sentence: "If you don't have a network, you don't need the Windows fire wall".
But while declaring himself "ready to defend the flag of the common country against the common foe," he added a crucial qualification.
IN announcing on Monday that her daughter Bristol was five months pregnant, Sarah Palin, John McCain's choice for a running mate, added a quick qualification that might, in another era, have eliminated the potential for embarrassment: The 17-year-old girl was to be married to the 18-year-old father of the baby.
Nevertheless, a report from the Medical Research Council (UK) [ 12] that followed the York Report added a further qualification on the viewpoint of the aesthetic component of fluorosis by stating: "Further studies should determine the public's perception of dental fluorosis with particular attention to the distinction between acceptable and aesthetically unacceptable fluorosis".
When challenged, later in the same press conference, Trump added a few qualifications, but then doubled down on the issue the next day using his chief of staff's son as an example.
