Medical conditions are not the only factor considered in these cases. Other factors condtibute to ones inability to work. Age makes a huge difference. For one thing, older people cannot compete in the market to get jobs. Employers prefer to hire younger workers. So the rules make it easier for people who are 50 years and older to qualify for disability benefits. Education will make a difference also but the next most important factor is the person's ability to communicate in English. If the person cannot communicate in English, there are many fewer jobs the person will be able to do. A 45 year old non-English speaking person will get the same advantage under the rules as a 50 year old English speaking person. Two 45 year olds, one English speaking one non-English speaking people are not able to compete for jobs at an equal level. The goal of the rules is to reflect the actual realities in the job market depending on differences in age, education and experience.
There are many factors other than how long you can sit, stand, walk, lift and carry that prevent people from being able to work. "Vocational Experts" testify about these. Some people have to be very close to a bathroom all the time and need unscheduled breaks. Some people have problems seeing anything smaller than a 50 cent piece, but their vision is other wise Ok to drive etc. Some people have terrible skin conditions on their hands that make it very painful to use their hands on a regular basis. Some people are required by their doctor to raise their feet to waist level. Some need to take rest breaks while laying down. A vocational expert will tell the judge that no employer will hire someone with any of those issues. Therefore, even if they can stand for two hours, they still are not employable. Your doctor needs to explain this to the Judge.