The difference between X ray machine in medical exam for work abroad & in tertiary hospital x ray machine,,?

during my medical exam for work abroad they found a "Pulmonary Fribrosis on my upper right lung" so i go for second opinion in a known tertiary hospital & again for chest x ray ..but the result was negative..what is the problem regarding this one..does it matter on the machine or the procedure...because during my agency clinic x ray they did not let me hold my breath, right away when i was about to hold my breath the technician said its already finshed ..{all i know since i am a ex abroad the technician will let you hold your breath}.......whereas on the hospital they let me hold for about 1 second then finished ..or is it matters on the x ray machine they are using since it is bound for middle east applicant right now i;m planning to go back the agency clinic to have a x ray again for finalization ...pls i need answer regarding about this one..thank you